Multi-render passes

Multi-render passes reduce the need to use render layers, thus reducing compute times for scene translation and rendering. If you work with complex multi-layered compositions, rendering may also be several times faster.

Using multi-render passes, you can render an unlimited number of render passes and group them into render pass sets.

For advanced users, you can also select a subset of the objects or lights in your scene to contribute to each render pass. This subset is called a render pass contribution map. Render pass contribution maps allow you to perform scene segmentation at render time.

Currently, the multi-render pass workflow is supported for the following shaders:

Setting up your scene to use multi-render passes

To set up multi-render passes, do the following:

Create render passes using the Passes tab in the Render Settings window and the Create Render Passes window. The Passes tab is available when you select mental ray as your renderer. Click the New Pass button in the Passes tab to open the Create Render Passes window, and select the render passes that you want to create.
See Create Render Passes window for more information.
Use the Passes tab to associate render passes with each layer and each pass contribution map.
See Passes tab for more information.
Use the render pass Attribute Editor to set your render pass options, such as the framebuffer type, or the number of channels for your render pass output. You can even create render pass presets.
See Render pass Attribute Editorfor more information.
Optionally, if you want to create several render passes, you can group them into a render pass set. Create a render pass set using the Passes tab in the Render Settings window.
See Passes tab for more information.
Use the Relationship Editor to manage the membership of your render pass set. Select Window > Relationship Editors or click in the Passes tab.
See Relationship Editor for more information.

Related topics

Render Layer Editor

Available render passes

Choose from the following render passes:

NoteOccasionally, you may notice aliasing on the edges of your render passes that does not exist in your overall beauty pass. This occurs because the mental ray adaptive sampling algorithm only refines sampling in areas of high contrast in your main beauty pass and not your individual passes. For example, an edge that appears in a material pass, but not in a beauty pass, may be under-sampled. The aliasing does not appear in your composited image. However, you can smooth out the edges for your individual passes by enabling the Contrast All Buffers option in the Render Settings window, Quality tab so that the adaptive sampling algorithm analyzes the contrast in all color frame buffers being rendered, rather than for just the master beauty pass.

Render Pass	Description
2D Motion Vector	Relative motion (in raster coordinates) of objects in your scene; in other words, how far each pixel is moving between two frames. Vector is expressed in normalized pixels.
3D Motion Vector	3D motion vector in world space. In mental ray for Maya, the 3D motion vector is expressed in internal space.
Ambient	Ambient contribution of the surface. In Maya, this is the material color multiplied by the ambient light color. See Render pass Attribute Editor for more information on the attributes for this pass.
Ambient Irradiance	Amount of ambient light received by the surface. See Render pass Attribute Editor for more information on the attributes for this pass.
Ambient Occlusion	Ambient occlusion contribution from both self ambient occlusion as well as primary ambient occlusion, which is derived from surrounding objects. You must enable Ambient Occlusion in the Render Settings: Features tab in order to use this render pass.
Ambient Material Color	Reflectivity of the material with respect to ambient light. See Render pass Attribute Editor for more information on the attributes for this pass.
Beauty	Final color computed by mental ray for Maya. See Render pass Attribute Editor for more information on the attributes for this pass.
Camera Depth / Camera Depth Remapped	Extracts the distance between the camera and the intersection point. Choose between normalized distance and real scene distance. See Camera Depth render pass attributes for more information on the attributes for this pass.
Coverage	mental ray Coverage frame buffer. This frame buffer offers only silhouette coverage. Self-coverage is currently not supported.
Custom Color / Custom Depth / Custom Label / Custom Vector	Use in conjunction with the writeToColorBuffer, writeToDepthBuffer, writeToVectorBuffer, and writeToLabelBuffer shaders to write data to the framebuffer. Or, create your own custom pass if you are using custom shaders. See mental ray render pass utility shaders for more information.
Diffuse	Diffuse shading of material. See Render pass Attribute Editor for more information on the attributes for this pass.
Diffuse Without Shadows	Diffuse pass without shadowing information. See Render pass Attribute Editor for more information on the attributes for this pass.
Diffuse Material Color	Provides constant diffuse color or textured diffuse color, excluding light contribution. See Render pass Attribute Editor for more information on the attributes for this pass.
Direct Irradiance	Direct light arriving at each sample location. See Render pass Attribute Editor for more information on the attributes for this pass.
Direct Irradiance Without Shadows	Direct irradiance without shadowing information. See Render pass Attribute Editor for more information on the attributes for this pass.
Glow Source	outGlow output of surface shaders; affected by pass contribution maps. See Render pass Attribute Editor for more information on the attributes for this pass.
Incandescence	Additive color. See Render pass Attribute Editor for more information on the attributes for this pass.
Incidence (Light/Normal)	Measures the difference between the direction of the light ray and the surface normal. If the surface normal is facing the light, this value is 1. If the normal is facing away from the light, the value is 0. Create a pass contribution map to isolate the light ray of your choice. If there is no pass contribution map in your scene, Maya performs its calculations based on the sum of all lights in your scene.
Indirect	Indirect lighting from final gather, global illumination, and caustics. See Render pass Attribute Editor for more information on the attributes for this pass.
Light Volume	Extracts all light-centric volume effects, for example, a light cone volume effect. See Render pass Attribute Editor for more information on the attributes for this pass.
Material Incidence (Camera/Normal)	Measures the difference between the direction of the camera ray and the surface normal. If the surface normal is pointing to the camera, this value is 0. If the normal is facing away from the camera, the value is 1. Any angle greater than 90 degrees is also translated to 1. If bump mapping is applied to the shading network, it will appear in this pass. See Render pass Attribute Editor for more information on the attributes for this pass.
Material Normal (Camera Space / Object Space / World Space)	Interpolated surface normal. Choose from one of Camera space, Object space and World space. If bump mapping is applied to the shading network, it will appear in this pass.
Matte	The object's matte, excluding transparency/opacity. This pass serves as the render layer compositing mask. Should be solid white in areas where objects are intersected. Independent of transparency/translucency. See Render pass Attribute Editor for more information on the attributes for this pass.
Normalized 2D Motion Vector	Relative motion (in raster coordinates) of objects in your scene; in other words, how far each pixel is moving between two frames. Pixel displacement is normalized to (0—1). Static objects are expressed with 0.5,0.5 values. See Normalized 2D Motion Vector render pass attributes for more information on the attributes for this pass.
Object Incidence (Camera/Normal)	Similar to the Material Incidence (Camera/Normal) pass but does not support bump mapping.
Object Normal (Camera Space / Object Space / World Space)	Similar to the Material Normal (Camera Space / Object Space / World Space) pass does not support bump mapping.
Object Volume	Extracts all object-centric volume effects, for example, smoke that is contained in a glass object. Also includes volume particles, volume fur, and fluids. See Render pass Attribute Editor for more information on the attributes for this pass.
Opacity	The object's opacity, which is derived from transparency/refraction. In compositing, the object's opacity can be controlled independently from the render layer matte. See Render pass Attribute Editor for more information on the attributes for this pass.
Raw Shadow	Similar to the Shadow pass but calculated only with respect to the irradiance in the scene. See Render pass Attribute Editor for more information on the attributes for this pass.
Reflection	Reflection results. Includes self-reflection, primary reflections, secondary reflections and environment reflections. See Render pass Attribute Editor for more information on the attributes for this pass.
Reflected Material Color	The reflected color parameter of the material. Pure constant reflection color or textured reflection. Used as a reflection matte to determine where reflection would be revealed (colored and noncolored). See Render pass Attribute Editor for more information on the attributes for this pass.
Refraction	Refraction results. Includes self-refraction, primary refraction, and environment refraction. See Render pass Attribute Editor for more information on the attributes for this pass.
Refraction Material Color	The transparency color parameter of the material. Pure constant refraction color or textured reflection. Used as a refraction/transparency matte to determine where refraction is revealed (colored and non-colored). See Render pass Attribute Editor for more information on the attributes for this pass.
Scatter	Scattering effects that result from the material’s scattering attributes (for example, Scatter Radius, Scatter Color). See Render pass Attribute Editor for more information on the attributes for this pass.
Scene Volume	Extracts all scene-centric volume effects such as fog, layered fog, haze, and so forth. See Render pass Attribute Editor for more information on the attributes for this pass.
Shadow	Pure shadow contribution for both self-shadowing as well as direct shadows. The shadow pass can be luminance or colored shadows. Takes into account material contributions. See Render pass Attribute Editor for more information on the attributes for this pass.
Specular	Specular shading. The specular component is modulated differently depending on the type of material associated with the object. For example, Phong, PhongE, Blinn, and Anisotropic materials produce specular contributions differently. On a Phong material, the specular pass can be modulated using cosine power and specular color. See Render pass Attribute Editor for more information on the attributes for this pass.
Specular Without Shadows	Similar to Specular but without shadow occlusions. See Render pass Attribute Editor for more information on the attributes for this pass.
Translucence	Back shading contribution revealed on the front surface. See Render pass Attribute Editor for more information on the attributes for this pass.
Translucence Without Shadows	Similar to Translucence but without shadows. See Render pass Attribute Editor for more information on the attributes for this pass.