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The shading engine node (also known as the shading group node) is the node that associates shaders with geometry. The shading group is a special type of object set that, in addition to containing geometry, defines a number of "shading ports" that control how the geometry in the set will be shaded. Each port is the starting point of a shading network.

The shading group has 3 shading ports:1) surface shading port - The shader that is connected to this port will control the appearance of the "surface geometry" contained in the shading group. Maya currently has 4 surface geometry types:- NURBS surfaces - polygonal meshes - subdivision surfaces - particle systems using the "blobby" software render modeFor each of these object types, the renderer will evaluate the "outColor" and "outTransparency" attributes of the shader attached to the surface shader port to determine the color and transparency of the objects, respectively.2) volume shading port - The shader that is connected to this port will control the appearance of the "volume geometry" contained in the shading group. Maya currently has 3 volume geometry types:- light fogs - environment fog - particle systems using the "cloud" or "tube" software render modesThe renderer will evaluate the "outColor" and "outTransparency" attributes of the shader attached to the volume shader port to compute the color and transparency of these volume objects.3) displacement shading port - The shader that is connected to this port will be invoked for the purpose of displacement-mapping all of the surface geometry in the shading group. The renderer will evaluate the "displacement" attribute of the shader attached to the displacement shader port for this purpose. The surface shader port will then be used to shade the displaced geometry.Following shading port is for mental ray for maya exclusively.1) material shading port2) shadow shading port3) volume shading port4) photon shading port5) photon volume shading port6) displacement shading port7) environment shading port8) light map shading port9) contour shading portIt should be noted that the type of the actual shading port attributes is irrelevant, as they exist only to establish a connection between the shading group and the root node of a shading network. Connecting *any* attribute of a shader to the shading port is sufficient to establish this connection. For this reason, the port attributes are declared as type Tdata, meaning that any type of attribute can be connected to them.
Node name Parents MFn type Compatible function sets
shadingEngine objectSet kShadingEngine kBase
kNamedObject
kDependencyNode
kShadingEngine

Related nodes

objectSet

Attributes (26)

displacementShader, imageShader, miContourAlpha, miContourColor, miContourColorB, miContourColorG, miContourColorR, miContourEnable, miContourRelativeWidth, miContourShader, miContourWidth, miCutAwayOpacity, miDisplacementShader, miEnvironmentShader, miExportMrMaterial, miExportShadingEngine, miExportVolumeSampler, miLightMapShader, miMaterialShader, miOpaque, miPhotonShader, miPhotonVolumeShader, miShadowShader, miVolumeShader, surfaceShader, volumeShader

Long name (short name) Type Default Flags
surfaceShader (ss) generic typed data NULL outputinputconnectable
The surface shader port. The node connected to this, the most commonly used port, will have its "outColor" and "outTransparency" attributes evaluated to sample the color and transparency of surface geometry in the shading group. Surface geometry types include NURBS surfaces, polygonal meshes, subdivision surfaces, and particles using the blobbly surface rendering mode.
displacementShader (ds) generic typed data NULL outputinputconnectable
The displacement shader port. The node that is connected to this port will have its "displacement" attribute evaluated to sample the displacement values for surface geometry in the shading group.
volumeShader (vs) generic typed data NULL outputinputconnectable
The volume shader port. The node that is connected to this port will have its "outColor" and "outTransparency" attributes evaluated to sample the color and transparency of volume objects in the shading group. Volume geometry types include light fogs, environment fog, and particles using the cloud or tube rendering modes.
imageShader (is) generic typed data NULL outputinputconnectable
Currently unused port.
miExportMrMaterial (mimt) bool false inputconnectablestorable
Controls usage of default mayabase material shaders, which are used by default. If enabled, the mayabase material shaders won't be applied at all but any custom mental ray node will.
miOpaque (miop) bool false inputconnectablestorable
Set the opaque material flag in mental ray for known non-transparent materials. If miOpaque is set, the material will not cast reflraction or transparency rays and its alpha will be always 1. This allows certain optimizations that improve rendering speed.
miCutAwayOpacity (mico) float 0.0 inputconnectablestorable
This is is an opacity threshold: all surface points that are less opaque than specified by this attribute will be considered non-existant. E.g. a value of 0.05 removes all surface points with a transparency of 95% or more.
miExportShadingEngine (mise) bool false inputconnectablestorable
Apply the mayabase shadingengine shader required for mayabase surface shaders also to custom mental ray surface nodes.
miMaterialShader (mims) generic typed data NULL outputinputconnectable
Port to connect custom mental ray node of type material shader.
miShadowShader (miss) generic typed data NULL outputinputconnectable
Port to connect custom mental ray node of type shadow shader.
miExportVolumeSampler (mism) bool false inputconnectablestorable
Apply the mayabase volumesampler shader required for mayabase volume shaders also to custom mental ray volume nodes.
miVolumeShader (mivs) generic typed data NULL outputinputconnectable
Port to connect custom mental ray node of type volume shader.
miPhotonShader (mips) generic typed data NULL outputinputconnectable
Port to connect custom mental ray node of type photon shader.
miPhotonVolumeShader (mipv) generic typed data NULL outputinputconnectable
Port to connect custom mental ray node of type photon volume shader.
miDisplacementShader (mids) generic typed data NULL outputinputconnectable
Port to connect custom mental ray node of type displacement shader.
miEnvironmentShader (mies) generic typed data NULL outputinputconnectable
Port to connect custom mental ray node of type environment shader.
miLightMapShader (milm) generic typed data NULL outputinputconnectable
Port to connect custom mental ray node of type lightmap shader.
miContourShader (mics) generic typed data NULL outputinputconnectable
Port to connect custom mental ray node of type contour shader.
miContourEnable (mice) bool false inputconnectablestorable
Enable contour detection and storage for contour output rendering. If miContourEnable is on, following contour settings will be used instead of miContourShader. miContourEnable enables contour shading for all objects associated with this shading engine.
miContourColor (micc) float3 inputconnectablestorable
miContourColor specifies the color of the contour lines.
miContourColorR (micr) float 1.0 inputconnectablestorable
Red component of contour color.
miContourColorG (micg) float 1.0 inputconnectablestorable
Green component of contour color.
miContourColorB (micb) float 1.0 inputconnectablestorable
Blue component of contour color.
miContourAlpha (mica) float 1.0 inputconnectablestorable
Alpha value of contour lines.
miContourWidth (micw) float 1.25 inputconnectablestorable
Width of the contour lines in pixel.
miContourRelativeWidth (mirw) bool false inputconnectablestorable
If miContourRelativeWidthoff, miContourWidth is specified as (fractional) number of pixels. If on, miContourWidth is specified in percents of the horiztonal image resolution thus maintaining the relative contour size if the resolution changes.