Advanced Render 2.
ADVANCED RENDER Programming Team Christian Losch, Philip Losch, Richard Kurz, Tilo Kühn, Thomas Kunert, David O’Reilly, Cathleen Poppe. Plugin Programming Sven Behne, Wilfried Behne, Michael Breitzke, Kiril Dinev, Per-Anders Edwards, David Farmer, Jamie Halmick, Richard Hintzenstern, Jan Eric Hoffmann, Eduardo Olivares, Nina Ivanova, Markus Jakubietz, Eric Sommerlade, Hendrik Steffen, Jens Uhlig, Michael Welter, Thomas Zeier. Product Manager Marco Tillmann. QA Manager Björn Marl.
MAXON Computer End User License Agreement NOTICE TO USER WITH THE INSTALLATION OF ADVANCED RENDER (THE “SOFTWARE”) A CONTRACT IS CONCLUDED BETWEEN YOU (“YOU” OR THE “USER”) AND MAXON COMPUTER GMBH ( THE “LICENSOR”), A COMPANY UNDER GERMAN LAW WITH RESIDENCE IN FRIEDRICHSDORF, GERMANY. WHEREAS BY USING AND/OR INSTALLING THE SOFTWARE YOU ACCEPT ALL THE TERMS AND CONDITIONS OF THIS AGREEMENT. IN THE CASE OF NON-ACCEPTANCE OF THIS LICENSE YOU ARE NOT PERMITTED TO INSTALL THE SOFTWARE.
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which the date of the purchase according to the invoice is decisive). The Licensor is free to cure the defects by free repair or provision of a faultless update. (2) The Licensor and its suppliers do not and cannot warrant the performance and the results you may obtain by using the Software or documentation. The foregoing states the sole and exclusive remedies for the Licensor’s or its suppliers’ breach of warranty, except for the foregoing limited warranty.
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Contents Introduction ..........................................................................................................1 Registration ........................................................................................................................................... 1 Installation............................................................................................................................................. 1 Training...............................................................
Glow properties................................................................................................................................... 59 Ring properties .................................................................................................................................... 60 Beam properties .................................................................................................................................. 60 Highlights filter limitations ..............................
Settings.............................................................................................................................................. 146 Astro Tab ........................................................................................................................................... 148 Clouds Tab ......................................................................................................................................... 150 Volumetric Tab....................................
INTRODUCTION • 1 Introduction Welcome to Advanced Render, the ultimate CINEMA 4D module for rendering with realism. With Advanced Render you will be able to add realistic lighting to your scenes with ease; simulate the beautiful patterns of focused light known as caustics; apply accurate depth of field; use post effect filters for highlights and glow to create realistic effects such as the sun being reflected by high-gloss car paint, and much more.
1 Global Illumination
Global Illumination• 5 1. Global Illumination (GI) GI gives you an easy way to enhance the realism of your renders. Global Illumination (hereafter referred to as GI) simulates the natural behavior of light, bouncing rays from surface to surface to produce photographic quality illumination. For a general introduction to GI, look up ‘what is GI?’ in the index. Image © Andreas Calmbach. You use two dialogs to set up GI.
6 • Global Illumination Render Settings On the GI page define the basic properties of the GI effect such as its general strength and accuracy. GI, drop-down list To switch on GI, enable the GI option. Using the drop-down list you can choose from four GI modes: Standard This is the standard GI mode; it works in the same way as described later in this chapter in the ‘What is GI?’ section. Standard mode is not suitable for animation.
Global Illumination• 7 In this mode only the following parameters will be available: Strength, Accuracy, Diffuse Depth and Stochastic Samples. Camera Animation If the only object that moves in your animation is the camera, there is no need to recalculate GI for each frame. Instead enable this option to calculate GI just once. The GI data will be reused for all frames, giving you the same effect in a fraction of the usual render time. If the option is disabled, GI will be recalculated for each frame.
8 • Global Illumination Accuracy This controls the general quality of the GI. Aim for a good balance between the best quality (a shading point for each image pixel) and the fastest result (a low number of shading points). You can set values from 0% (least accurate) to 100% (most accurate). A poor result with 3% Accuracy. A good result with 70% Accuracy. The Accuracy setting is optimized by Min Resolution and Max Resolution.
Global Illumination• 9 Prepass Size When you render a GI scene, a prepass image is rendered first that displays the shading points as dots. This setting defines the ratio of the prepass image size to the final render size. The default value is 1/1 — always use 1/1 for final rendering. Lowering the setting reduces render time but also lowers the render quality. Diffuse Depth This setting is the maximum number of reflections and refractions for each ray of light. You can enter values from 1 to 100.
10 • Global Illumination Min Resolution, Max Resolution Min Resolution and Max Resolution optimize the Accuracy setting to speed up rendering. Without optimization, more shading points would be created than are needed. For example, with an Accuracy of 100%, a shading point would be created for each image pixel. CINEMA 4D optimizes the accuracy by concentrating the shading points in the areas where they are most needed.
Global Illumination• 11 Figure 3: Max Resolution set too low. Figure 4: A good Max Resolution setting. The best settings for Min and Max Resolution depend on the scene and getting them right is the key to fast, high-quality GI. The easiest way to find the minimum and maximum values is to take the size of the whole scene (excluding cameras, lights, floors and sky objects) and divide it by how often you want a sample on the surface of an object.
12 • Global Illumination To summarize: Set Min Resolution to scene length ÷ biggest gap between shading points. Set Max Resolution to scene length ÷ smallest gap between shading points. If you notice artefacts in the rendered image such as dark patches, gradually increase the values for Accuracy and Max Resolution. The artefacts should disappear once the values are sufficiently high. Recompute With Recompute, the GI data from a previous render can be reused to speed up rendering.
Global Illumination• 13 Identical Noise Distribution Sometimes the rendered image can appear very grainy when using Stochastic mode (see picture below), especially when using a low value for Accuracy or Stochastic Samples. This type of grain is often called ‘noise’. If Identical Noise Distribution is enabled, the noise will be identical (or at least very similar) for each frame of the animation. If the option is disabled, the noise will be different for each frame.
14 • Global Illumination Generate GI, Strength Enable this option if the material should reflect/refract GI onto other objects. Use the input box to set the strength of the GI generated. You can enter a value from 0 to 10,000%; 100% represents normal strength. Receive GI, Strength If this option is enabled, the material will receive GI. The input box defines the strength of the effect. Saturation The area in the center uses a high Saturation value.
Global Illumination• 15 Another important measure is to keep your geometry clean. Overlapping polygons or double polygons will cause an unnecessary concentration of samples on a clean surface and will cause the rendering process to spend more time calculating that area than required. Examples Because GI calculations are complex, it is very difficult to give general advice on which parameters need to be adjusted and by how much in order to arrive at the optimum result.
16 • Global Illumination The values used are shown in red. The parameter that changes across the row is shown at the top of the list.
Global Illumination• 17 What is GI? GI is an option that improves the photorealism of rendering. It works by calculating more realistic lighting for the scene. Although GI can produce lifelike images, it is disabled by default because it adds to the render time. Image © Carles Piles GI lets you dramatically improve the realism of images by adding indirect lighting to the scene — normal rendering calculates direct lighting only. Direct light is light that an object receives directly from light sources.
18 • Global Illumination Consider the following example where a wall meets a floor. In Figure 1 (GI disabled), there is no indirect light at all. In Figure 2 (GI enabled), you can see a color tint on the white areas near the join. This is caused by the color bands reflecting light onto the white areas. The white bands reflect light as well — look closely and notice how the color bands are bleached near the join. Fig. 1: GI disabled. Fig. 2: GI enabled.
Global Illumination• 19 Figure 4: Lighting via a luminous material on a Sky object. The GI algorithm GI works in a similar way to raytracing. First, rays are sent from the camera into the scene. A shading point is created at each point where a camera ray hits an object’s surface (Figure 5). Next, a number of special rays, called stochastic samples, are sent out from each shading point.
20 • Global Illumination Each time a stochastic sample hits a surface, a new dome of stochastic samples is sent out from that point. This second generation of stochastic samples may in turn trigger a third wave of stochastic samples and so on. This chain reaction of events continues with further generations of stochastic samples created until a limiting factor has been reached — as specified in the GI settings.
Global Illumination• 21 With HDRI. Try re-rendering your old scenes with HDRI. You’ll be surprised by how much of a difference HDRIs can make! Types of HDRI There are three main types of HDRI: HDRI Latitude/Longitude, HDRI Light Probes and HDRI Horizontal/Vertical Cross. HDRI Latitude/Longitude These images are distorted in such a way that they can be mapped onto a sphere (or a Sky object) using spherical mapping which produces perfect results. This type of HDRI works best in CINEMA 4D.
22 • Global Illumination HDRI Light Probes These HDRIs are generated by taking pictures of a reflective sphere. HDRI Horizontal/Vertical Cross These HDRIs are laid out like an unfolded cube and are designed to be mapped onto a cube that surrounds the scene. In CINEMA 4D, however, we recommend using the Latitude/Longitude type instead. Usage At www.debevec.org/Probes/ you’ll find a number of HDRIs that you can use for testing.
Global Illumination• 23 If you want the HDRI to be the only source of light in the scene, remember to switch off the Auto Light option in the Render Settings (Options page). Depending on the intensity of the HDRI texture, the scene may be too dark or too bright. You can adjust the HDRI brightness in the following ways: Using the Strength parameter in the render settings (GI page) and the Global Illumination Generate/Receive options on the Illumination page of the material that uses the HDRI texture.
24 • Global Illumination Some HDRIs come as Probe or Cross projection types. To get the best result in CINEMA 4D, these should be converted to Latitude/Longitude (spherical) maps and projected onto a Sky object. For this purpose there are two plugins included — Convert HDR Cross and Convert HDR Probe — which are available from the Plugins > Advanced Render menu. Choosing one of these commands opens a file selector. Select the HDR Probe or Cross image that you want to convert.
2 Caustics
CAUSTICS • 27 2. Caustics Image © Janine Pauke. With Advanced Render’s powerful caustics engine, you can create realistic patterns of focused light such as the bright patches that a whiskey tumbler casts onto a wooden floor. For a general introduction to caustics, including commonly-used terms, look up ‘What are caustics?’ in the index. You use three dialogs to set up caustics. On the Caustics page of the render settings, set the basic properties of the caustics effect such as its strength.
28 • CAUSTICS Surface Caustics Enable this option to switch on surface caustics. Surface caustics, low strength. Surface caustics, normal strength. Surface caustics, high strength. Volume Caustics Enable this option to switch on volume caustics. Volume caustics, normal strength. Volume caustics, high strength. Ensure that your caustics light source is volumetric.
CAUSTICS • 29 Strength This sets the general brightness of the caustics effect. Step Size (volume caustics only) With volume caustics, photons are saved in the photon tree at regular intervals as defined by this value. For example, if the volume caustic effect is 100 m long, you might set Step Size to 5 m so that 20 different values are saved for each photon. Lowering Step Size increases the accuracy of the effect but increases the render time also. A lower Step Size produces a brighter effect.
30 • CAUSTICS Samples set to 1. Samples set to 30. Recompute With Recompute, the caustics data from a previous render can be reused to speed up rendering. This saves the time it takes to calculate the caustics effect, but keep in mind that a new calculation will be required if you make major changes to the scene such as if you move a caustics-generating light to a new position. See also ‘Save Solution’. Use the Recompute drop-down list to choose when caustics should be recalculated.
CAUSTICS • 31 Single Animation Solution If the only object that moves in your animation is the camera, there is no need to recalculate caustics for each frame. Instead, enable this option to calculate caustics just once. The caustics data will be reused for all frames, giving you the same effect in a fraction of the usual render time. In addition to saving render time, this option helps you to create flicker-free caustics animation. If the option is disabled, caustics will be recalculated for each frame.
32 • CAUSTICS Radius This specifies how close photons must be to one another in order to be interpolated. Higher values tend to produce better results but they also take longer to render. Radius = 1; individual photons can be seen as points of light because they are not interpolated together. Radius = 10. Radius = 100. Samples This defines the maximum number of photons within the Radius that are used to calculate the effect.
CAUSTICS • 33 Light settings You can switch on caustics for any light source and refine the effect using the light’s Caustics page in the Attribute manager. Surface Caustics Enable this option to switch on surface caustics for the active light source. Energy Surface caustics with low Energy (10,000). Surface caustics with high Energy (20,000). This defines the total starting energy for the surface caustics photons. The Energy value mainly controls the brightness of the caustics effect.
34 • CAUSTICS Photons The Photons value affects the accuracy of the caustics effect – increasing the value produces a better result. However, larger values also mean longer render times. The value defines the number of photons that will be used to calculate surface caustics. The best value is usually between 10,000 and 1,000,000 although this depends on factors specific to the scene such as the distance between the light source and the causticsgenerating object. You can enter values up to 100,000,000.
CAUSTICS • 35 This defines the total starting energy for all volume caustics photons. It affects the brightness of the effect as well as the maximum number of reflections or refractions for each photon. Photons This parameter controls the accuracy of the caustics effect. Increasing the value produces a better effect, but higher values mean longer render times also. The value is the number of photons the light will send out for volume caustics.
36 • CAUSTICS Figure 2: The metal ring shows a caustics effect generated by a reflective surface. Figure 3: The bright “tail” extending from the sphere is a volume caustics effect. Advanced Render enables you to create both surface caustics and volume caustics. A surface caustics effect shows up on object surfaces only — examples are the transparent sphere and the ring (in both cases, the effect shows up on a surface: the floor).
CAUSTICS • 37 Caustics are calculated in a very different way to global illumination and raytracing. Global illumination and raytracing send rays from the camera into the scene. With caustics, however, photons are sent from the light source into the scene. Each photon is given a starting energy. A photon’s energy is reduced as it passes through the scene and is reflected or refracted by object surfaces (Figure 4). Figure 4: A photon refracted by a sphere. Figure 5: An example of double-caustics.
38 • CAUSTICS Once all photons have ended their journey in one way or another, the values in the photon tree are interpolated to calculate the surface caustics effect for the image. Double-caustics are possible. This happens when an object focuses caustics onto another object that generates caustics. See Figure 5. The volume caustics algorithm Volume caustics are calculated in a similar way to surface caustics.
CAUSTICS • 39 Once you can see the photons, increase the Photons value (and perhaps the Energy) until you achieve a good caustics effect. To fine-tune the sharpness, adjust Radius and Samples on the Illumination tab (Material Editor). Volume Caustics If you notice artefacts of the type illustrated below when rendering volume caustics, on the light’s Visibility tab, try reducing the Sample Distance value. This will, however, add to the render time.
3 Depth of Field
DEPTH OF FIELD • 43 3. Depth of Field With Advanced Render’s Depth of Field filter you have complete control over the sharpness of your pictures. For example, you can blur in front of the focus only, behind the focus only, or both. Using gradients, you can easily modify the progression from sharpness to full blur. In addition you can add a tint to your renders that gets stronger towards the horizon, for effects such as atmospheric perspective where the strength of a blue tint suggests depth.
44 • DEPTH OF FIELD Blur Strength This parameter defines the general strength of blurring. Other parameters modify this strength such as Distance Blur and Radial Blur. Note that if you set Blur Strength to 0% there will be no blurring at all, even when the other blur parameters are set to high values. Distance Blur The Distance Blur value refines the strength of blurring. For example, if you set Blur Strength to 80% and Distance Blur to 50%, the strength of full blurring will be 40% (50% of 80%).
DEPTH OF FIELD • 45 Figure 1: Rear blur only. Figure 2: Weak front and rear blur. Figure 3: Strong front and rear blur. Scene by Stephan Oberlaender. Figure 4: Background blur. Background Blur Use this parameter to control the strength of blurring for CINEMA 4D’s Background object (Objects > Scene > Background). All other types of objects are unaffected by Background Blur. See Figure 4.
46 • DEPTH OF FIELD Radial Blur Radial blur is blur that gets stronger from the picture’s center outwards. Use the input box to define the strength of the effect. Autofocus This option can be enabled to simulate the autofocus feature of a real camera. The object in the center of the view will become the focal point, i.e. the object in the center will be perfectly sharp. So that the object does not have to be exactly in the center, you can enter a tolerance value.
DEPTH OF FIELD • 47 The gradient is similar to gradients in other applications that you have probably seen before. The handles on the bottom of the gradient, known as knots, are used to set the color and position of colors in the gradient. To add a knot just click in an empty area below the gradient and a knot of the color at that position will be added. To remove a knot just click on it and drag it away from the gradient.
48 • DEPTH OF FIELD Intensity A measurement for the intensity of the currently selected knot. Edit Alpha, Display Result Some gradients such as those for tint have two further options: Edit Alpha and Display Result. These options give you three gradients in one. Two of these are gradients that you can define: a gradient that defines the color and a second gradient — called the alpha gradient — that controls the color gradient’s opacity.
DEPTH OF FIELD • 49 Lens Details Using the settings on the Lens Details page, you can simulate the popular movie effect where objects that are brightly lit in places slip out of focus. Artefacts will appear in the bright areas. Use the Lens Details to adjust these artefacts. Lens Shape set to Triangle Lens Sharpness The sharpness of the lens artefacts. Lens Intensity The brightness of the lens artefacts.
50 • DEPTH OF FIELD Tint Using these parameters, you can add tints that take the scene’s depth into account. For example, you can add a blue tint to your renders that gets stronger towards the horizon (aerial perspective); simulate the orange tint of the horizon on the sunset; or recreate the deep, dark cold blue of a moonlit scene. You can also simulate the orange tint of daylight film used to photograph interiors and the blue tint of interior film when it is used to photograph exteriors.
DEPTH OF FIELD • 51 3. Use Ranges enabled, Use Camera Ranges disabled. Do not confuse these parameters with the like-named parameters of the Camera object. The tint range is defined by the values Front Start, Front End, Back Start and Back End (not the camera parameters) based on the camera’s focus. This enables you to define the tint independently of the Depth of Field settings.
52 • DEPTH OF FIELD
4 Highlights
HIGHLIGHTS • 55 4. Highlights With Advanced Render, you have great flexibility when adding lens flares and glows to your pictures. Dozens of parameters enable you to adjust almost any aspect of the glow, from the number of beams to the size of each element. In addition, you can add flares and glows to specular highlights to achieve complex effects with ease, such as jewels that sparkle, flying logos where metallic or shiny objects catch the light or water surfaces that shimmer on a sunny day.
56 • HIGHLIGHTS After you’ve selected Highlights on the Effects page, the Highlights settings will appear. These settings are described in the following pages. Render settings Effects All parameters with a circle next to their name can be animated. For details on how to animate parameters, please refer to your CINEMA 4D reference manual. Because Highlights depends on the brightness of rendered pixels, you may get different results when you change seemingly unrelated parameters.
HIGHLIGHTS • 57 Keep in mind that if you set the value too high, the threshold may not be reached and, as a result, no highlights will be added. Minimum Flare Intensity, Maximum Flare Intensity These parameters define the intensity of the highlights. The intensity is calculated dynamically based on the brightness of the rendered pixels. The higher you set the Minimum value, the more intense the highlights will be, although never brighter than the value for Maximum.
58 • HIGHLIGHTS From top left to bottom right: Fine Regular, Fine Random, Wide-angle, Zoom, Camcorder, Searchlight, Streaks 1, Streaks 2, Star 1, Star 2, Flashlight, Sun, Broken Star, Fine Yellow Star, Soft Streaks 1, Soft Streaks 2, Blue. Use Object ID The Object ID corresponds to the object buffers defined in the Compositing tag. Suppose there are two objects in the scene and you want each object to use its own highlights settings.
HIGHLIGHTS • 59 Glow Editor Using the Glow Editor, you can edit the various properties of the highlights such as the ring elements, beam colors and number of beams. There are four main areas in the Glow Editor dialog: one area for the glow itself (top left), one for the surrounding ring (Ring, center left), one for beams (bottom left) and one for the type and look of the beams (top right). Glow properties Glow Glows consist of separately editable elements.
60 • HIGHLIGHTS This value defines the aspect ratio for the glow. A value of 1 results in a circular glow, whereas values greater or less than 1 produce a horizontal or vertical ellipse. Color To set the color for the glow element, click the box to the right of Size. The color picker for your operating system will open. Pick the desired color.
HIGHLIGHTS • 61 Size Here you set the overall size of the beam element as a percentage of the screen’s size. A value of 100% represents the distance from the center of the screen to the edge of the screen. R (aspect ratio) This value defines the aspect ratio for the beam element. A value of 1 results in a circular shape, whereas values greater or less than 1 produce a horizontal or vertical ellipse. Color To set the color of the beam element, click the box to the right of Size.
62 • HIGHLIGHTS Random Beam Length Enable this option if you want the lengths of the beams to be varied. Star-like To have the beams arranged in a star-like pattern, enable this option. The beams will become thicker towards the center. For a realistic star, use a low number of thick beams. Highlights filter limitations Problems may occur in areas where highlights are seen in reflections or behind transparencies.
5 Glow
GLOW • 65 5. Glow Advanced Render gives you a powerful filter for creating glow effects. With it you can simulate the glow of incandescent lights, lightning bolts, LEDs, neon lights, monitor screens, the reflection of the sun by high-gloss car paint and much more. The Glow filter also enables you to: Control glow transparency. Make the bright areas of the rendered picture glow. Use additive or non-additive glow; prevent unwanted overexposures. Restrict the glow to edges or specific colors.
66 • GLOW Render settings Glow All parameters with a circle next to their name can be animated. For details on how to animate parameters, please refer to your CINEMA 4D reference manual. To make an object glow uniformly, enable Color and set Balance to a high value. Object ID The Object ID corresponds to the object buffers defined in the Compositing tag. Suppose there are dozens of objects in the scene and you want only one of them to glow.
GLOW • 67 High Size value. Low Size value. The Size value also affects the glow’s brightness. This is because the intensity of the glow (defined by Intensity) is spread over the entire glow. Intensity The Intensity is a measurement for the transparency of the glow. A value of 0 represents full transparency (i.e. no glow). Increase the value for more opacity and thus a brighter glow. High Intensity value. Low Intensity value. Back Intensity This parameter controls the glow effect for dark surfaces.
68 • GLOW High Back Intensity value. Low Back Intensity value. You can also use Back Intensity to achieve negative glow for effects such as dust clouds and smoke clouds. For negative glow, set Back Intensity to a low value. Use a low Back Intensity value for negative glow. Luminosity The glow effect is usually additive and brightens pixels. Using Luminosity you can reduce the glow’s additive nature, causing the glow to darken. A value of 0% results in a diffuse, dusty cloud.
GLOW • 69 Luminosity set to a low value. Luminosity set to a high value. Back Luminosity This parameter gives you a more refined way to control luminosity by checking the brightness of the rendered pixels. The glow and the rendered pixels are combined in an additive process. Use the Back Luminosity value to adjust this process. The Back Luminosity parameter is especially useful for correcting glows that are too bright and washed out.
70 • GLOW The color is also important when you want objects to glow with a uniform color regardless of their rendered brightness. Click the color box, choose the desired color and set Balance to a high value. Define an object ID and assign a Compositing tag to the glowing object with the corresponding object buffer enabled. Glow Edges You can restrict the glow effect to object edges by enabling this option.
GLOW • 71 Zoom Scale There are two ways to zoom objects in the viewport: 1. By increasing the camera’s Focal Length value. 2. By moving the camera closer to the objects or vice versa (see ‘Distance Scale’). Enable Zoom Scale if you are zooming via the Focal Length value and you want to zoom the glow as well as the objects. Zoom Scale disabled. The glow still has the same thickness when you zoom the object. Zoom Scale enabled. When you zoom the object, the glow is also zoomed.
72 • GLOW Balance The Balance parameter controls how bright the rendered pixels must be in order to trigger glow in those areas. With the default value of 0%, only the brightest areas will glow. With a value of 100%, all areas will glow with the same intensity. However, note that a dark glow will be used for the dark areas. Use the Object ID parameter to restrict the glow to the desired objects.
GLOW • 73 Nonclamped Color Attenuation Using the parameters on this page, you can restrict the glow to rendered pixels that are within a defined brightness range. Set this range by entering values into the boxes for Min Intensity and Max Intensity, where 100% represents bright white (RGB 255/255/255). Enter values above 100% if you want restrict the glow to nonclamped colors (i.e. colors above RGB 255/255/255).
74 • GLOW Use Key Color Glow restricted to a key color. You can restrict the glow to a particular color. Use the color box to choose this ‘key color’. Since most rendered surfaces are gradations of color rather than a single tone, you can also specify a tolerance value for the key color, which you enter into the Color Variation box. If you set Color Variation to a value that is too low, such as 0%, you may find that only a few pixels will glow.
GLOW • 75 Distance Attenuation Using these parameters, the glow effect takes the Z-buffer into account (i.e. the distance from the camera to each surface) or the glow is adjusted radially around an object. Start Range, End Range The Start Range and End Range define a range over which the glow changes with distance.
76 • GLOW Distance Position There are two settings. Z-Buffer Start Range and End Range refer to the Z-buffer, i.e. the distance from the camera to the object’s surface. 3D Pos Start Range and End Range refer to the position of the object’s axis in 3D space. The glow spreads out radially from the axis. Using gradients You can use gradients to refine the following glow properties from the Glow page: Size, Intensity, Luminosity and Color (see ‘Glow’ entry).
GLOW • 77 The direction of surface normals can be taken into account by the glow, causing the glow’s color or intensity to change depending on a surface’s direction. For details on surface normals, please refer to your CINEMA 4D documentation. Glow color that changes depending on the direction of each surface normal. Shininess This parameter controls the glow’s highlights.
78 • GLOW Noise Exhaust fumes, flickering flames, lightning bolts and puffy clouds are just a few of the effects you can achieve with the help of noise. A small amount of noise can also add to the realism of most soft glow effects. Noise applied to colors that depend on the direction of surface normals. The page for noise contains many settings that may seem daunting at first.
GLOW • 79 Gaseous noise. Fire noise. Electric noise. Use the previous examples as a rough guide only. Entirely different results are possible depending on the settings used for the other Noise parameters. Once you’ve chosen the Noise Type, fine-tune the effect using the other parameters on the Noise page. Intensity Use this parameter to control the intensity of the noise effect. Increase the value to increase the brightness. A value of 0 results in no glow. High Intensity value. Low Intensity value.
80 • GLOW Brightness This controls the brightness of the noise effect. Reduce the value if the glow is too bright and washed-out. Luminosity Luminosity affects the settings for Color and Ground Glow. It controls the strength of additive mixing for these parameters when they are mixed with the other image elements. Luminosity set to a low value (bottom left) and a high value (top right). Color Here you can choose the color of the noise.
GLOW • 81 Scale The fractal turbulences are scaled using this parameter. From top to bottom: Scale set to a low value, a medium value and a high value. Peak Blend To blend out dark areas, set Peak Blend to a high value. Only the brightest areas of the glow will remain. For a photographic negative effect, enter a negative value. From top to bottom: Peak Blend set to a negative value, a low value and a high value. Details The Details parameter controls the amount of fractal branching.
82 • GLOW From top to bottom: Details set to a low value, a medium value and a high value. Phase Animate this parameter if you want to animate the fractal cloud. In general, use a small Phase change over time for slow gaseous motion and use a high Phase change for rapid effects such as fire. Try various rates until you arrive at the desired result. Angle, Drift Angle and Drift are intended for animation only and are ideal for clouds.
GLOW • 83 From top to bottom: Ground Glow disabled, Ground Glow enabled and Ground Glow without noise. Stretch Use this parameter to stretch the fractals in a particular direction (the value entered for Angle). Increase the value for more stretching. From top to bottom: Stretch set to a low value, a medium value and a high value. Glow filter limitations Problems may occur in areas where glows are seen in reflections or behind transparencies.
84 • GLOW
6 Vector Motion Blur
VECTOR MOTION BLUR • 87 6. Vector Motion Blur To render VMB as a separate pass, on the Render Settings > Effects tab, click the Channels button and choose Post Effects from the menu that appears. Next to scene motion blur and object motion blur, vector motion blur (VMB) gives you a third means of blurring moving objects.
88 • VECTOR MOTION BLUR Render settings Shutter Angle Shutter Angle set to a low value (left) and high value (right). The Shutter Angle defines the length of the blur trail. You can even use very high values, which would be even more unrealistic but may produce interesting effects. Realistic results should be achieved with the default angle of 180° and moderate object speed. Phase, Density From left to right: Phase values of 100%, 50% and 0%.
VECTOR MOTION BLUR • 89 Density set to a low value (left) and high value (right). The Density value defines the coverage of the blur in the image. The Phase value defines the position of the blur. The following Phase values should serve as a reference: 0%: behind the object. 50%: the same length on both sides of the object. 100%: in front of the object (the blur moves ahead). Samples, Sample Radius Samples set to a low value (left) and high value (right).
90 • VECTOR MOTION BLUR Samples allow you to set the resolution or smoothness of the blur. Low values result in a grainy look, while more samples increase both the quality and the render time. The higher the Sample Radius, the less crisp the blur will look. Weighted Trails Weighted Trails disabled (top) and enabled (bottom). The Weighted Trails option uses a different algorithm that allows the trails to fade out towards the end, resulting in a realistic trail.
7 Subsurface Scattering
SUBSURFACE SCATTERING • 95 7. Subsurface Scattering The subsurface scattering effect (SSS) does exactly what it says on the tin: light that penetrates translucent objects is broken, scattered and sometimes partially (or fully) absorbed or even colorized. The visual effect is that of an object that appears to be glowing, especially in thin areas. SSS is a volumetric effect and works best with closed objects (see picture below). It’s surprising just how many real-world objects are translucent.
96 • SUBSURFACE SCATTERING Adjust the Absorption Filter color and the Absorption parameter. These define the material’s color and its ability to transmit light. Now modify the Samples and Minimum Thickness. Done! Material Editor / Attribute manager settings Absorption Filter These colors will only appear in the rendered image if they are also present in the penetrating light. If in doubt use a white light, which contains all colors.
SUBSURFACE SCATTERING • 97 Strength Strength set to a low value (left) and high value (right). Strength generally defines how bright the SSS effect will look in the material. Adjust this parameter first when setting up a new SSS material. Filter Length Filter Length set to a low value (left) and high value (right). The Filter Length parameter defines how deep the gradient travels into the material. The right edge of the gradient corresponds to the Filter Length value.
98 • SUBSURFACE SCATTERING Samples Samples set too low. The Samples parameter is a common feature in CINEMA 4D. Wherever physical effects are simulated, such as a ray of light that diminishes in intensity over a set distance, samples are taken that measure the intensity at various locations. The more samples taken, the more precise the results are. However, the render time increases with increasing sample-count.
SUBSURFACE SCATTERING • 99 Use Normals enabled. In this case, the normals define where the material is located (normals are always assumed to point outwards). When using this mode, the objects and their normals have to be well defined. This also means that even intersecting objects can be calculated correctly.
100 • SUBSURFACE SCATTERING
8 Sub-polygon Displacement
104 • SUB-POLYGON DISPLACEMENT 8. Sub-polygon Displacement Solar eclipse in Friedrichsdorf, Germany: the displacement texture on the left (color texture not pictured) is responsible for the SPD on the right. The height of the SPD has been exaggerated for illustrative purposes. In principle, sub-polygon displacement (referred to as SPD in the following text) is similar to displacement: an object is deformed during rendering based on a texture’s grayscale palette or, in some modes, color palette.
SUB-POLYGON DISPLACEMENT • 105 The quality of the rendered image is much better than using a texture map in the bump channel. Don’t forget that CINEMA 4D has shaders that can be animated to create sophisticated animations. Combine different animated noise shaders with the level shader to create a moving ocean surface, for example. Material Editor / Attribute manager settings You’ll find the SPD settings on the Displacement tab in the Material Editor or Attribute manager.
106 • SUB-POLYGON DISPLACEMENT Subdivision Level Balls of slime (two sphere primitives with their Render Perfect option disabled) with a subdivision of 2,4 and 8 (from bottom to top). This is where you determine the SPD subdivision. This goes for the entire object to which the material has been applied. It can be well worth the trouble to delete the object’s hidden sides in order to reduce the number of surfaces that must be subdivided.
SUB-POLYGON DISPLACEMENT • 107 Round Geometry Round Geometry disabled (left) and enabled (right). Since SPD cannot calculate a normal Phong shading when it is applied, a special algorithm similar to that of the HyperNURBS is used to ensure that the object is rounded before the SPD is rendered. This is specially designed to smooth surfaces that appear facetted after SPD rendering. Contours (polygon edges that have no adjoining polygons) remain unaffected if Round Contours is enabled.
108 • SUB-POLYGON DISPLACEMENT Round Geometry and HyperNURBS As mentioned above, Round Geometry uses an algorithm similar to the one used by HyperNURBS. In some cases, you can do without HyperNURBS entirely and use SPD to smooth instead. If you use SPD and HyperNURBS on the same object, keep in mind that the subdivisions will be multiplied because the SPD subdivision will be applied to the object after it has been subdivided by HyperNURBS.
SUB-POLYGON DISPLACEMENT • 109 For this example, an SPD texture was applied to a Plane consisting of only one polygon with Round Geometry and Round Contours both enabled. The result on the left is what can normally be expected: the texture’s density has not been changed in the rounded areas. In contrast, the result pictured on the right shows that the texture was projected prior to rounding and was squashed during the rounding process.
110 • SUB-POLYGON DISPLACEMENT As you can see in the example above, the enabled Best Distribution option changes the direction of the displacements towards the Phong edges. The closer a displacement is to the edge, the closer it is brought to this edge and the closer it follows the virtually rounded Phong normal. The benefit to enabling this option is that in most cases it will ensure a soft, continuous transition of the SPD over Phong edges.
9 Color Mapping
114 • COLOR MAPPING 9. Color Mapping General Top left, the over-exposed rendering without Color Mapping. Why Color Mapping? Surely you are aware of the fact that an image rendered with GI is very bright in some areas and very dark in others. A balanced allocation of color and brightness would be nice in order to be able to achieve a consistent lighting. Many may think that this can simply be done in Photoshop. Not quite.
COLOR MAPPING • 115 Settings For these settings, the following applies: Although they look quite inconspicuous, you should take the time to try them all out. Basically, though, “Exponential” and “HSV Model” should be left active. Use the “Multipliers” to fine-tune your image. Exponential Left, “Exponential” not active; right, “Exponential” active. The color dispersion will be controlled exponentially, not linearly (option not active).
116 • COLOR MAPPING Affect Background Here you can define whether or not Color Mapping should affect the background (if one is present), such as Sky or Background objects. Dark Multiplier / Bright Multiplier These settings basically let you strengthen or weaken dark and light colors. The following image contains numerous samples using various values for both settings. Of course, the same values can lead to different results in your own scene.
COLOR MAPPING • 117 For each image on the left, the image is shown to the right with different values.
10 Ambient Occlusion
AMBIENT OCCLUSION • 121 10. Ambient Occlusion General Ambient Occlusion can be found in two locations within the application: As a channel shader (“Material Editor / Texture / Effects). As a global effect and calculated throughout the entire scene in “Render Settings... / Ambient Occlusion”. Options in both dialog windows are identical with the exception of the “Apply to Scene” setting.
122 • AMBIENT OCCLUSION Top left without, top right with “Ambient Occlusion” in the “Diffusion” channel. Ambient Occlusion (AO) offers, within certain limits, a fast alternative to GI. Ambient Occlusion determines to what degree each individual surface point is exposed and colors it accordingly. Let’s say your scene contains no floor and is surrounded on all sides by a sky. The AO shader will determine to what extent each visible area “sees” the sky.
AMBIENT OCCLUSION • 123 Color Minimum Ray Length Use the “Color” option to define the color gradient that AO assigns, dependent on exposure. Normally, it will be a simple custom black to white gradient but other colors can aslso be defined. The left end of the gradient represents areas with minimal exposure (bottom of sphere) and the right side represents areas with maximum exposure. Be aware of the fact that these gradients will be treated as grayscale, depending on the material channel.
124 • AMBIENT OCCLUSION In general, lower values are recommended that offer results as in the left-most example above. Dispersion From left to right: “Dispersion” values of 0%, 50% and 100%. During each AO calculation, several rays (“Samples” ) will be emitted for each point within a virtual hemisphere in the scene. These samples check to see if any geometry lies within the “Maximum Ray Length”. “Dispersion” determines to what extent these samples will be taken into account on the hemisphere’s surface.
AMBIENT OCCLUSION • 125 Of course a maximum number of samples can be calculated for the entire scene. This would take very, very long to calculate and it doesn’t make any sense since a scene contains many areas in which a relatively small number of samples would suffice. That’s what the “Minimum Samples” and “Maximum Samples” settings are for. Use them to specifically control critical and less critical areas of your scene (and interpolate between them).
126 • AMBIENT OCCLUSION Consistent in all images: “Minimum Ray Length” “0”, “Dispersion” “100”, and “Contrast” “10”. Minimum Samples Use this setting to define the number of samples that should be used in less critical areas. Maximum Samples Use this setting to define the number of samples that should be used in critical areas. The exact number of samples will be dispersed dynamically in correlation to the “Accuracy” setting. Contrast Use this setting to adjust the AO effect’s contrast.
AMBIENT OCCLUSION • 127 Use Sky Environment The AO shader in the Environment channel, Use Sky Environment active, no light source. If AO is used in the “Diffusion” material channel, a separate light source must be used (even if it’s only the Auto light). AO also works without a light source if the Sky object is used as “Illumination”. If “Use Sky Environment” is active, the reflected sky color will be multiplied onto the final AO image.
128 • AMBIENT OCCLUSION Self Shadowing Only Left: “Self Shadowing Only” not active. Right: “Self Shadowing Only” active. Floor and wall are separate objects. When this option is active, separate objects will not “see” each other, they will only “see” themselves. Render Settings In the Ambient Occlusion menu of the “Render Settings...” you will find the AO settings, the same ones you will find in the AO shader. All settings function identically.
11 SKY
SKY • 131 11. SKY General Creating a Sky To create a sky, simply follow these steps: 1. In the menu at the top of your interface, select “Plugins / Sky / Create Sky“. A Sky object and an Environment object, with a Sky shader volume material assigned to it, will be created. 2. In the Object Manager, double-click on the newly created Sky object. Switch to the „Beginner“ tab and select one of the available skies from the “Weather“ menu. 3.
132 • SKY A sun light source, similar to an “Infinite Light”, whose properties are automatically defined by the time of day with respect to position, color, and brightness. Hard shadow and area shadow are located in the Sky Manager’s “Illumination“ tab. A moon light source, similar to an Infinite Light, whose properties are automatically defined by the time of day with respect to position and brightness. It uses a “Hard” shadow.
SKY • 133 The Sky Manager is Sky’s control center. This is where you can edit just about any setting that has to do with Sky’s effects, with the exception of those parts of volumetric clouds that possess their own objects or tools. You can also open the Sky Manager by double-clicking the Sky object or the Sky volume shader. The Sky Manager’s settings can also be found in the Attribute Manager. The following descriptions use the Sky Manager.
134 • SKY Object Tab Priority This sets the priority of the internal Sky expression. You can find more information regarding this in the “CINEMA 4D Tags” chapter, p. 696 in your CINEMA 4D reference manual. Example: You’ve placed your own light source to serve as the sun, but the light source’s color is overwritten by the internal Sky expression. Since XPresso tags receive a higher priority than Sky, you can use an XPresso tag to assign a color to your light source, thereby overriding Sky.
SKY • 135 Beginner Tab This is the only Sky tab that will be available when in “Simple” mode. Weather Select one of the available presets. It will then be shown in the preview window above the menu selection. Time Click on “Now” to select the current date and time. Since the positions of the stars lie in direct correlation to time zones and the location on earth from which they are viewed, you can select a specific time zone and date. You can read more under “Date and Time”.
136 • SKY Date and Time Tab The same house at different times of day: 9 a.m., 1 p.m. und 5 p.m. Since the position of the stars (as well as your position on the earth’s surface) lies in direct correlation to time zones, you select a set time and date for your simulation. Of course both of these properties can be animated, although there are some specifics you should be aware of (see below).
SKY • 137 Time This is where you enter the time and date of your Sky simulation. Click on “Now” to set your scene to the actual date and time on your computer. The file will be saved with the date and time defined here and won’t be changed, unless you select the option “Current Time”. If you want to simulate the sun’s position in a time zone different from your own, you must set the time manually. Time and date will always be displayed in the status bar at the bottom of the Sky Manager.
138 • SKY Animate Date / Time If neither option is active, no interpolation between time keys will take place. Lets say you have two time keys, the first with a value of 22.07 08:54, the second with a value of 26.09 18: 54. If you were to interpolate these two values it would be impossible to estimate how long this interpolation would take. This is why both options have the following function, respectively: Animate Date: The time remains constant, only the day will change.
SKY • 139 General Tab Turbidity Various “Turbidity“ settings: At the top, evening, at the bottom, midday. The sky’s many colors are a result of light passing through moisture or other types of particles in the atmosphere. In CINEMA 4D, the amount of particles present in the atmosphere is called “Turbidity”.
140 • SKY If “Turbidity” is set to “0”, the atmosphere will have no “substance” and your sky may be displayed almost black, even at midday. Higher values will basically lead to foggy, more smoky, and more colorful effects. Other effects can also be achieved in conjunction with “Atmosphere Strength”, described below, although they will not change in a linear fashion when a parameter is changed. So, as is so often the case – experiment.
SKY • 141 Max. Lens Flare Glow Lens Flare Glow and Lens Flare Reflection. This slider determines the intensity of the lens flare glow. A value of “0”= no lens flare glow. Max. Lens Flare Reflection If the lens flare bothers you, move the slider to a value of 0% to turn it off, or adjust the intensity until you’re happy with the result. Custom Horizon This option lets you adjust the color of the sky’s (the celestial sphere’s) gradation. Max.
142 • SKY Color Here you can define the color gradient that will be vertically projected onto the sky (celestial sphere) in the following manner: Left: In close proximity to the horizon Center: In the height of the sun (or to the “Max. Altitude” value) Right: In proximity to the current time Horizon Start Here you can adjust the height of the horizon. In a scene in which the floor does not continue “endlessly”, it can occur that you can see below the horizon.
SKY • 143 Atmosphere Strength This option affects the brightness of the atmosphere, i.e. the effect created by the “Turbidity” value. A low “Atmosphere Strength” value will give you a black or “deep space” effect, whereas a very high value will give you a blinding white effect. If you want to animate a trip from the earth’s surface to the moon, for example, the “Atmosphere Strength” value should be animated from a higher value down to 0%.
144 • SKY Earth Radius (kilometers) The earth’s radius is scalable. The height and dispersion of volumetric clouds is determined by this scale factor. If “Adjust Altitude” in the “Volumetric” tab is active, volumetric clouds will be arranged on a concentric sphere to reflect the curvature of the earth. The smaller the earth’s curvature, the more spherical the volumetric clouds will become. Min. Magnitude The “Magnitude” value represents the apparent brightness of stars on a firmament.
SKY • 145 Show Constellations / Color Option “Show Constellations“ active with “Color“ set to red. Constellations can be displayed in any color. If you set anti-aliasing to “Best” in the “Render Settings...” menu, the constellations (as well as the “Grid”, which is mentioned below) will be smoothed when rendered. Moon Distance Scale / Sun Distance Scale If you encounter problems with the light sources integrated into the sun or moon (e.g.
146 • SKY Location Tab The positions of constellations on the celestial sphere lie in direct correlation to date, time, and the location from which they are viewed from earth. In the “Location” tab you can select the city in which your simulation should be located, or you can add your own location, including all coordinates and time zones. Don’t let all these settings confuse you; in most cases, selecting the location nearest you from the comprehensive list of preset cities will be fine.
SKY • 147 Only if “Time” is set to “Custom” will the following three options be made available: “Daylight Savings”, “Time Zone” and “DS Time Zone”. Daylight Savings This is where you enter the Daylight Saving Time of your present location or the location where your simulation will take place. For the United States, for example, you would select “First April Sunday to Last Oct. Sunday”. The two lower Daylight Saving Times apply to the southern hemisphere.
148 • SKY Delete Lets you delete the currently selected city. Astro Tab General The blue aura surrounding the moon is a result of the corresponding “Turbidity” setting in the “General” tab. Use the “General” tab to define all details pertaining to the positions of stars, moon, and planets in our solar system. Of course the position of the stars lies in direct correlation to, date, time (“Date and Time” tab), and location on the earth from which they are viewed (“Location” tab).
SKY • 149 Object All of the following settings use the selected planet or moon as a reference, and can be changed independently of one another. In addition to the moon, you will also find all planets of our solar system. Auto When active, this option will link to “Location” and “Date and Time”, and allow the moon and planet’s positions to be changed manually. Deactivate this option if you want to manually enter values for “Azimuth” and “Altitude”.
150 • SKY Azimuth: The direction of a celestial object, measured clockwise around the observer’s horizon from the North (Z-axis). Altitude: The angle of a celestial object measured upwards from the observer’s horizon. These values are shown for informational purposes only. They can, though, be adjusted manually by deactivating the “Auto” option. RA / Declination / Distance These values are also shown for informational purposes only and cannot be adjusted manually.
SKY • 151 In the “Clouds” tab you can edit the look of your 2D clouds (3D clouds can be edited in the “Volumetric” tab). A special method is used to project 2D clouds onto the celestial sphere to give a realistic impression of cloud cover that stretches across the entire firmament. Each cloud layer is created from the already well-known Noise types (see “Noise 2D/3D” under “Channel Shaders”). Here you will find a depiction of all types of Noise).
152 • SKY Rolloff Left, “Rolloff” deactivated (black gradient); right, “Rolloff” default settings. This grayscale gradient causes the sky to fade to the cloud color near the horizon, thus giving the cloud cover a realistic look as it approaches the horizon. The left side of the gradient represents the zenith, the right side of the horizon. Black=transparency; white=color of the clouds. Noise A small selection of Noise types.
SKY • 153 Here you can select the type of noise with which your 2D clouds should be created. By clicking on the button with the arrow on it (to the right of the noise name) you can open a window in which the different noise types can be viewed and selected. To the right of this button is the image preview for the cloud layer.
154 • SKY Color Define the color of your cloud here; its color will be independent of the sun’s color or that of other sources of light. Only the cloud’s brightness will be adjusted to match the sun. Altitude Three different types of noise at different altitudes. Set the height of each cloud layer. If you take a look out of the window you will notice that clouds often consist of several layers.
SKY • 155 Density Left, low “Density” value; right, higher “Density” value. Simply put, “Density” defines the contrast of the clouds. If a low value is used, the clouds will be very transparent, especially towards the edges. The higher the value, the more planar and homogeneous the clouds will be. Coverage Left, low “Coverage” value; right, higher “Coverage” value. This is the most important cloud setting. With it you define the degree of cloud coverage.
156 • SKY Thickness Left, low “Thickness” value; right, higher “Thickness” value. “Thickness” is the measure of the degree to which the sunlight will be dispersed or absorbed. This can be equated with the lighting of the clouds by the sun. Lower values result in the clouds being brightened more by the sunlight, higher values result in darker clouds. Transparency Left, high “Transparency” value; right, low “Transparency” value.
SKY • 157 Anim. Speed The animation speed defined here relates to the noise structure – not the position of the clouds! The higher the value, the more the clouds will billow. You have probably seen slow motion clips of billowing clouds literally being created “out of the blue”; this setting lets you create a similar effect. If you also animate the cloud position (use the “Pos. N-S” and “Pos. W-E” settings), the result will be very realistic.
158 • SKY Volumetric Tab Settings Show Bounding Box The bounding box is the area of a volumetric cloud that will be rendered. A bounding box is automatically created when a cloud is painted and corresponds to the cloud’s dimensions in 3D space. Bounding boxes can be rescaled interactively. Simply select the Move Tool and drag the orange grabbers. Editor Color This is the color of a cloud’s bounding box, which is not selected in the editor.
SKY • 159 Adjust Altitude Activating this option places the volumetric clouds in such a manner as to reflect the curvature of the earth, more or less a partial sphere. This hemisphere’s diameter measures 2x(earth radius + cloud altitude). You can find the exact earth radius in the “General” tab. If the default earth radius is used, the effect of this function will be limited.
160 • SKY Noise Type Various noise types. Here you can select from numerous noise types (see p. 788, “Channel Shaders” in your CINEMA 4D reference manual). You can also click on the small button to the right of the selection to select a noise type visually. Contrast The higher the contrast, the more visible the noise structure will be. Size Top, large “Sclae” value, bottom, low “Scale” value (using the same noise type). Use this setting to scale the noise.
SKY • 161 Noise Speed If a value greater than “0” is entered here, the clouds will billow, i.e. their edges will slowly change. Lights Drag all lights that should affect the volumetric clouds into this field. If this field is left empty, the volumetric clouds will only be affected by the sun and moon. Rainbow Tab Just as in reality, two types of rainbows are available (here, for demonstration purposes, with a high “Max. Strength” value).
162 • SKY Settings Max. Strength Use this slider to adjust the rainbow’s transparency. The second rainbow will be created according to the properties of the first. The lower the value, the more transparent the rainbows will be rendered. We suggest you use unobtrusive, transparent rainbows – less is more. Turbidity Dependent In reality, if there’s no rain (or moisture in the air), there’s no rainbow. Sky regulates the density of the moisture in the air via “Turbidity” (in the “General” tab).
SKY • 163 If you think rainbows are too narrow, try entering inner and outer values of 30° and 50°, respectively, for the first rainbow. Start / End Clip Imagine an animated airplane approaching from the distance out of the rainbow. In the distance, the airplane is behind the rainbow; as it approaches it will eventually cover the rainbow. Such effects are possible using these settings.
164 • SKY Fog Tab Friedrichsdorf, Germany in a fog bank. Thanks to Paul Everett for his “City Gen” plugin (www.tools4d.com). Now what would a sky simulation be without fog? Right, only half the rent. That’s why a fog system has been integrated into Sky. This is real volumetric fog, based on diverse types of noise shaders (see Noise 2D/3D in “Channel Shaders” ) that render less homogeneously and therefore more realistically. The fog stretches infinitely in a vertically adjustable fog bank.
SKY • 165 Settings Color This is the color the fog should assume. This color will not be affected by other colored light sources, although the sun’s color can be multiplied with the fog’s color (if the “Illumination Intensity” setting described below is set to greater than “0” ).
166 • SKY Start / End Side view left: “Start” = “0” (fog begins at the ground); right: “Start” / “0”. Each example contains strong reduction in “Density Distribution”. The fog bank, which extends infinitely on the X- and Z-axes, must at least be limited in its vertical extension. Otherwise you wouldn’t be able to see anything in the resulting soupy fog. The “Start” and “End” settings determine where the fog should begin and end (starting from the ground, Y=0).
SKY • 167 Density Distribution Imagine the graph rotated counter-clockwise by 90°. This graph regulates the density between the “Start” and “End” settings. You can read more on how to use this graph in “Function Graphs” on p. 136 in your CINEMA 4D reference manual. The left end of the graph represents the “Start” value, the right the “End” value. In order to be able to imagine how the density distribution works, imagine the graph rotated counter-clockwise by 90° and projected into the scene.
168 • SKY Scale Left, a low “Scale” value; right, a higher “Scale” value. Use these settings to scale the noise’s structure along the X-, Y-, and Z-axes. Higher values result in more realistic fog banks, even intermittently creating “holes”. Movement Use this setting to move the fog along the X, Y or Z-axis. The structure of the noise will not be affected. Note: If you want to animate the noise structure so it “billows”, set “Animation Speed” to a value greater than “0”.
SKY • 169 Noise Strength Increasing noise strength from left to right. The noise strength can pretty much be compared to a contrast slider – the higher you set the noise strength, the more dense the fog will become in already dense areas, and the more transparent it will become in lessdense areas. A value of “0” will result in a homogenous, even fog with no noise. Shadow Intensity Top: “Shadow Intensity” set to “0”; Bottom: “80%”.
170 • SKY You can define how strong shadows should be cast by adjusting “Shadow Intensity”. Careful! Render times increase with each increase in shadow strength! Illumination Intensity A sandstorm: White fog is colored yellow by the sun. Incrementally increase the value to greater than “0” if you want the color of the sun to combine with that of the fog. To be exact, a color value between 1 and the color of the sun will be ascertained and multiplied by the fog’s color.
SKY • 171 Sun Shadow Type Select which type of shadow, if any, the sun should cast. You can select between “Hard” and “Area”. Generate GI You probably already know this option from CINEMA 4D’s material settings (see “Material Channel Illumination” in your Advanced Render reference manual). Careful: The radiated GI applies only to the sky and not to other elements such as fog, rainbows, etc. Clouds that cast shadows can, by all means, affect GI.
172 • SKY Sunbeams shining through the clouds can be quite a beautiful and useful effect. In order to make the sunbeams visible, a few prerequisites must be met: From the point of view of the camera, the sun should be mostly hidden behind the clouds. Otherwise the sunbeams would simply shine in the direction of the camera and only a white glare will be seen. The cloud cover must be structured in such a manner that sunbeams can even pass through them, i.e. dense, with intermittent holes or clearing.
SKY • 173 Min. Brightness Left: low “Min. Brightness” value; right: high “Min. Brightness” value. Use this slider to determine at what minimum brightness value (internal) the sunbeam will become visible. Select a high value if you want to make only the brightest sunbeams visible, a low value if you also want to make weak sunbeams visible. The brightness of the rendered sunbeams is defined by “Intensity”.
174 • SKY Sky Objects Tab A Sky object can be used to easily create a large green moon with a hole in the center. Wouldn’t it be a shame if all you could see in the sky were stars and planets? Let’s say you want to smack a space station or some other object onto your sky – with Sky objects, no problem.
SKY • 175 Note: Even though most image files are square, Sky uses a circular shape to place the image. This circular shape covers the surface of the image to its edges; what lies outside of this circle will then be “cut away”. Settings The following settings will be created automatically when an object is placed into the sky. All settings, except for the image file’s name, can be edited by clicking on the corresponding value. Name This is the name of the original image file.
176 • SKY Illum. Large: “Illum.” on; Small: “Illum.” off If this option is active, a sickle-shaped shadow will be cast onto the Sky object (on the sun side), giving the impression it is a spherical object being lit by the sun. Naturally, it wouldn’t make much sense to use this option on non-spherical shapes and should then be deactivated. Simply check or uncheck the option to activate or deactivate it. Intensity “Intensity” regulates the Sky object’s transparency.
SKY • 177 If you want to define your own light sources for moon and sun, this is the place to be. Simply drag a light source from the Object Manager into the “Sun” or “Moon” field. Note: Sky will still determine the light source’s Location, color and brightness according to the time of day. You can define a constant color using the “Color” setting (under “Custom Sun Color”) in the “General” tab.
178 • SKY 2. Select “Plugins / Sky / Cloud Tool”. Rotate your editor view so you’re looking up at the sky, and paint a cloud formation by clicking with and dragging the left mouse button. Avoid painting your clouds too close to the horizon since they will then be created too large. 3. If you want to create additional clouds, deselect all Cloud objects or click on the top-most Sky object in the Object Manager’s hierarchy.
SKY • 179 Objects can be used to define the shape of your cloud (the cloud does not have to be part of a cloud group). Note: Only those areas of the object used to define the shape of the cloud that lie within the cloud’s red bounding box (the box that is displayed when the cloud is selected) will be rendered. Use the “Transfer” function (“Functions / Transfer”) to place the object whose shape you want the cloud to assume at the cloud’s location.
180 • SKY The Cloud Group Object The “Cloud Group” object lets you vary the look of volumetric clouds that have been created using different methods. Each cloud has 5 settings that can be changed, each limited by “Min.” and “Max.” values: Altitude Falloff Luminance Falloff Transparency Falloff Color The settings of all subordinated clouds will be found here (depending on their “Mix” setting), providing the cloud’s “Override Group” setting is deactivated.
SKY • 181 The Cloud Object Settings Override Group If this option is active, a Cloud Group object will not affect this cloud, and the cloud’s settings can be changed individually. Mix When clouds are painted (and thereby newly created), the “Mix” value is randomly set to a value between 0% and 100%. This value determines where this particular cloud will lie within the defined parameters (Altitude, Luminance Falloff, Transparency Falloff, Color) of the parent Cloud Group.
182 • SKY Example: A cloud’s parent Cloud Group has a “Min. Altitude” of 5,000m and a “Max. Altitude” of 10000m. The “Mix” values below would give the cloud the corresponding altitudes: 0% = 5,000m 50% = 7,500m 100% = 1,0000m Note: Slight deviations in altitude can result if the “Volumetric” tag’s “Adjust Altitude” setting is active because this setting places clouds in a manner as to reflect the curvature of the earth. Altitude This is the height at which a cloud lies.
SKY • 183 Luminance Falloff Left a lower, right a higher “Luminance Falloff” value. “Luminance Falloff” regulates the amount of sunlight that is absorbed. The higher the value entered, the less sunlight that will be absorbed and the brighter the cloud will appear. Low values result in clouds being darker, more foreboding on the side opposite the sun. Clouds can be made so dark they look like black smoke.
184 • SKY Falloff Use this graph to define the cloud’s density falloff from the outside to its inner. Note: This function graph, and the “Distance” setting below it, will only be activated if an object has been assigned to the cloud, whose shape the cloud is to assume. Distance “Distance” is the area within which the function graph exercises influence. Keep Shape This option is only relevant if the object over which a cloud has been placed to give it its form has not been deleted.
SKY • 185 The cloud’s density points will only be completely visible (Cloud Tool “Display” tab) if the Cloud object and Cloud Tool have been selected. When tools other than the Cloud Tool are selected, only a reduced number of points will be visible, which speeds up workflow. Application Basically, there are two ways to work with the Cloud Tool: 1. Paint new clouds. See “General”. 2. Edit existing clouds. Activate the cloud you want to edit.
186 • SKY Settings Tool Tab Radius “Radius” displays a circle around the cursor within which a random cluster of cloud density points are distributed (as long as the left mouse button is pressed). As long as the left mouse button is pressed, new points will be painted. This can lead to interesting results if you don’t move the mouse while you paint. Large “Radius” setting, painted without moving the mouse.
SKY • 187 Density Identical brushstroke, one with higher, one with lower density. Use “Density” to define a cloud’s consistency. Higher values will result in more dense, even, and homogeneous clouds, whereas lower values will result in more scattered, less homogeneous clouds.
188 • SKY Smoothing Borders After having painted a cloud, its density is consistently even. This isn’t as realistic as it could be and may result in visible artifacting at the cloud’s edges. In fact, the cloud’s density should fade at its edges, and this is exactly what “Smooth Borders” does. In the image below, “Quality” (“Display” tab) was set to 100%, which ensures that every cloud density point is displayed. This can be seen best in the editor.
SKY • 189 Smoothing the Entire Cloud The following settings affect the entire cloud, not only its edges; density points may also be added. Smoothing makes clouds more fluffy, more cotton-like, as in the example below: At top: A newly painted cloud. At bottom: The same cloud after clicking on “Smooth All” several times. Strength Sets the strength (increases each time the button is clicked) with which smoothing should be applied to the selected cloud.
190 • SKY Render Preview Renders only the selected cloud(s). Create Sky Call this function up if the following objects and materials are not present in your scene: Sky object Sky volumetric material Environment object with applied Sky volumetric material These objects will then be added automatically. Connect Clouds Connects all selected volumetric clouds into a single (new) cloud. The old clouds will be deactivated.
SKY • 191 This is especially true when a volumetric cloud is positioned in the camera’s line of sight and in front of a PyroCluster volume tracer, or the other way around. In order to avoid this, you can assign a cube to the PyroCluster volume tracer, which will then calculate the volume for PyroCluster. What you should definitely avoid, though, is a spatial overlapping of volumetric clouds with PyroCluster clouds. There is no work-around for this.
192 • SKY
12 Tutorial
TUTORIAL • 195 12. Tutorial Global illumination For this tutorial we’ll use Advanced Render’s powerful global illumination engine to render an office lobby scene with natural lighting. There are two things to remember when modeling a scene for global illumination: 1. Controlling light is incredibly important. Global illumination scenes usually look best with hard shadows.
196 • TUTORIAL The skydome surrounds the entire lobby and the next step is to give the skydome a special material — a luminance-only material. The object’s illumination setting will be included in the global illumination calculation and fill out the lighting of the room just like the sky would in the real world. Create a new material and name it Sky. In the Material manager, double click on the new material’s preview to open the Material Editor. Disable the Color channel for this material.
TUTORIAL • 197 On the General page, change the light’s Type to Parallel and make the color of the light slightly yellow to imitate the sun. (R=100%, G=100%, B=96%, Br=170%. Or RGB = 255, 155, 244.) Set Shadow to Hard. Although the real sun is basically an omni light, the light that reaches earth is more of less parallel due to the huge distance involved. Position the light outside of the room and above. We will want to place it above and the window and some distance away.
198 • TUTORIAL Rendering the Scene Open the Render Settings (Render > Render Settings). We will be using the raytracer for this scene. This will give a high quality final render. Set Antialiasing to Best and set Filter to Still Image. As a rule, we should leave all the rest of the settings on the first page at their highest level. This is because there is no increase in rendering time unless they occur in the scene. (This scene will use Transparency With Refraction and Reflections for All Objects.
TUTORIAL • 199 Click the Path button, select a location and name for the rendered image and click Save. Go to the Multi-Pass page. Enable the Enable Multi-Pass Rendering option. This will save a new image with a separate layer for each channel we set on the Multi-Pass page. This is useful if later one aspect of our scene changes that does not affect every channel. When re-rendering, we need only to render the channel that has changed, saving us tremendous production time and effort.
13 Index
INDEX • 203 Index Symbols 3D clouds 177 3D Pos 76 A Absorption 97 Absorption Filter 96 Accuracy 124 Adjust Altitude 159 Altitude 149, 154, 175, 180, 182 Ambient Occlusion 121 Anim.
204 • INDEX Back Luminosity 69 Balance 72 Color 69 Dark glow 72 Distance Scale 71 Glow Edges 70 Luminosity 68 Object ID 66 Size 66 Zoom Scale 71 Glow Edges 70 Glow Editor 59 Angle (Rays) 61 Aspect ratio (Beam) 61 Aspect ratio (Glow) 59 Aspect ratio (Rays) 60 Beams 60 Breaks 61 Color (Glow) 60 Color (Rays) 60 Color (Ring) 60 Object ID 58 Random Beam Length 62 Random Distribution 61 Ring 60 Size (Glow) 59 Size (Rays) 61 Size (Ring) 60 Thickness 61 Type (Beams) 60 Type (Glow) 59 Width 61 Gradients 50 Cubic Bi
INDEX • 205 S sandstorm 170 Save as Preset 153 Scale (Noise) 81 Scale N-S / E-W 157 Scattering Length 98 Scene Objects Tab 176 Secrecy vi Self Shadowing Only 128 semi-spherical Area Light 132 Settings 136, 146 Shadow Intensity 169 Shape 188 Shininess 77 Show Constellations / Color 145 Show Stars 150 Shutter Angle 88 SKY 131 Sky 133 Skydome 195 SKY and PyroCluster 190 Sky and Weather 133 SKY Manager 132 Sky Objects Tab 174 Smoke 78 Smoothing Entire Cloud 189 Smoothing Tab 187 Smooth All 189 Smooth Borders 1
