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# Appendix B: Rendering attributes

Note

The shading process uses the long names for attributes, so it doesn’t matter what you use for short names.

## Output Attributes requested by Shading Groups

Name Long (short) | Data Type | Description
--- | --- | ---
displacement (d) | float | Output surface displacement distance along the surface normal
outColor (oc) outColorR (ocr) outColorG (ocg) outColorB (ocb) | float3 float float float | Output color
outGlowColor (ogc) outGlowColorR (ogr) outGlowColorG (ogg) outGlowColorB (ogb) | float3 float float float | Output glow color
outMatteOpacity (omo) outMatteOpacityR (omor) outMatteOpacityG (omog) outMatteOpacityB (omob) | float3 float float float | Output matte
outTransparency (ot) outTransparencyR (otr) outTransparencyG (otg) outTransparencyB (otb) | float3 float float float | Output transparency

## Rendering Attributes available per sample

Name Long (short) | Data Type | Description
--- | --- | ---
farPointCamera (fc) farPointCameraX (fcx) farPointCameraY (fcy) farPointCameraZ (fcz) | float3 float float float | used for volume, the far point of the visible interval in camera space
farPointObj (fo) farPointObjX (fox) farPointObjY (foy) farPointObjZ (foz) | float3 float float float | used for volume, the far point of the visible interval in object space
farPointWorld (fw) farPointWorldX (fwx) farPointWorldY (fwy) farPointWorldZ (fwz) | float3 float float float | used for volume, the far point of the visible interval in world space
filterSize (fs) filterSizeX (fsx) filterSizeY (fsy) filterSizeZ (fsz) | float3 float float float | Filter size in (u, v, w) with which to filter textures
infoBits (ib) | 32-bit unsigned integer | Passes information from one node that may be needed by another node. Using this field, a file texture node with advanced filtering turned on (such as Quadratic filtering) can be used simultaneously as both a color map and a bump map. When rendering, Maya computes the color map using advanced filtering, but computes the bump map without it since advanced filtering is incompatible with bump mapping.
lightDataArray (ltd) lightDirection (ld) lightDirectionX (ldx) lightDirectionY (ldy) lightDirectionZ (ldz) lightIntensity (li) lightIntensityR (lir) lightIntensityG (lig) lightIntensityB (lib) lightAmbient (la) lightDiffuse (ldf) lightSpecular (ls) lightShadowFraction (lsf) | lightData float3 float float float float3 float float float boolean boolean boolean float | Multi-attribute representing all lights linked to the shading group The light direction The light intensity Flag for ambient component Flag for diffuse component Flag for specular component Percentage shadowing of the current light, provided shadows are enabled on the given light
matrixObjectToWorld (mow) | floatMatrix | Transformation from object space into world space
matrixWorldToObject (mwo) | floatMatrix | Transformation from world space into object space
mediumRefractiveIndex (mrfi) | float | refractive index of the medium through which the incident ray was travelling before it hit the point being shaded
normalCamera (n) normalCameraX (nx) normalCameraY (ny) normalCameraZ (nz) | float3 float float float | Surface normal in camera space
numShadingSamples (ns) | char | Number of shading samples to take for this surface
objectId (oi) | int | unique ID for the object being shaded, may not be the same ID across frames
objectType (ot) | char | the rendering type (0=unknown, 1=surface, 2=volume(not particles), 3=blobby surface, 4=particle system, 5=image plane)
particleAge (pa) | float | age of the particle currently being shaded
particleColor (pc) particleColorR (pcr) particleColorG (pcg) particleColorB (pcb) | float3 float float float | per-particle color as provided by a particle color mapper
particleId (pid) | int | unique identifier for the particle being shaded
particleIncandescence (pi) particleIncandescenceR (pir) particleIncandescenceG (pig) particleIncandescenceB (pib) | float3 float float float | per-particle incandescence as provided by a particle incandescence mapper
particleLifespan (pls) | float | life-span of the current particle
particleTransparency (pt) particleTransparencyR (ptr) particleTransparencyG (ptg) particleTransparencyB (ptb) | float3 float float float | per-particle transparency as provided by a particle transparency mapper
particleWeight (w) | float | weight of the current particle
pixelCenter (pc) pixelCenterX (pcx) pixelCenterY (pcy) | float2 float float | center of the pixel currently being shaded in screen space
pointCamera (p) pointCameraX (px) pointCameraY (py) pointCameraZ (pz) | float3 float float float | xyz location of geometry in camera space
pointObj (po) pointObjX (pox) pointObjY (poy) pointObjZ (poz) | float3 float float float | xyz location of geometry in object space
pointWorld (pw) pointWorldX (pwx) pointWorldY (pwy) pointWorldZ (pwz) | float3 float float float | xyz location of geometry in world space
rayDepth (rd) | int | during raytracing, the depth of the current ray (the primary ray has a depth of 0)
rayDirection (rad) rayDirectionX (rdx) rayDirectionY (rdy) rayDirectionZ (rdz) | float3 float float float | The direction of the current intersection ray in camera space
rayOrigin (ro) rayOriginX (rox) rayOriginY (roy) rayOriginZ (roz) | float3 float float float | The origin of the current intersection ray in camera space
refPointCamera (rpc) refPointCameraX (rcx) refPointCameraY (rcy) refPointCamearZ (rcz) | float3 float float float | The current reference sample point that has to be shaded. Used in conjunction with reference objects.
refPointObject (rpo) refPointObjectX (rox) refPointObjectY (roy) refPointObjectZ (roz) | float3 float float float | The current reference sample point that has to be shaded. Used in conjunction with reference objects.
refPointWorld (rpw) refPointWorldX (rwx) refPointWorldY (rwy) refPointWorldZ (rwz) | float3 float float float | The current reference sample point that has to be shaded. Used in conjunction with reference objects.
tangentUCamera(tu) tangentUx (tux) tangentUy (tuy) tangentUz (tuz) | float3 float float float | The U tangent of the surface in camera space
tangentVCamera (tv) tangentVx (tvx) tangentVy (tvy) tangentVz (tvz) | float3 float float float | The V tangent of the surface in camera space
triangleNormalCamera (tnc) triangleNormalCameraX (tnx) triangleNormalCameraY (tny) triangleNormalCameraZ (tnz) | float3 float float float | Normal of the visible triangle in camera space.
uvCoord (uv) uCoord (u) vCoord (v) | float2 float float | texture UV coordinates in surface parametric space
uvFilterSize (uf) uvFilterSizeX (ufx) uvFilterSizeY (ufy) | float3 float float | The sample (filter) size
vertexCameraOne (vc1) vertexCameraOneX (c1x) vertexCameraOneY (c1y) vertexCameraOneZ (c1z) | float3 float float float | vertex one of the triangle currently being shaded in camera space
vertexCameraTwo (vc2) vertexCameraTwoX (c2x) vertexCameraTwoY (c2y) vertexCameraTwoZ (c2z) | float3 float float float | vertex two of the triangle currently being shaded in camera space
vertexCameraThree (vc3) vertexCameraThreeX (c3x) vertexCameraThreeY (c3y) vertexCameraThreeZ (c3z) | float3 float float float | vertex three of the triangle currently being shaded in camera space
vertexUvOne (vt1) vertexUvOneU (t1u) vertexUvOneV (t1v) | float2 float float | texture coordinate of the triangle currently being shaded
vertexUvTwo (vt2) vertexUvTwoU (t2u) vertexUvTwoV (t2v) | float2 float float | texture coordinate of the triangle currently being shaded
vertexUvThree (vt3) vertexUvThreeU (t3u) vertexUvThreeV (t3v) | float2 float float | texture coordinate of the triangle currently being shaded

## Rendering Attributes available per frame

Name | Data Type | Description
--- | --- | ---
cameraFarClipPlane (fcp) | float | Far clipping plane distance for camera view
cameraNearClipPlane (ncp) | float | Near clipping plane for camera view
hFilmAperture (hfa) | float | width of the film (inches) from the camera being currently rendered
hFilmOffset (hfo) | float | horizontal offsets of the film (inches)
isPerspCamera (ipc) | boolean | If TRUE (non-zero), camera is perspective projection, else it is orthographic
lensSqueezeRatio (lsr) | float | squeeze ratio of the camera being currently rendered
matrixEyeToNormPersp (etp) | floatMatrix | Transformation from camera (eye) space to normalized perspective space
matrixEyeToWorld (e2w or etw) | floatMatrix | Transformation from camera (eye) space to world space
matrixNormPerspToEye (pte) | floatMatrix | Transformation from normalized perspective space to camera (eye) space
matrixWorldToEye (wte) | floatMatrix | Transformation from world space to camera (eye) space
vFilmAperture (vfa) | float | height of the film (inches) from the camera being currently rendered
vFilmOffset (vfo) | float | vertical offsets of the film (inches)
xHighRenderRegion (hrx) | int | resolution of the image in x
yHighRenderRegion (hry) | int | resolution of the image in y
xLowRenderRegion (lrx) | int | always 0
yLowRenderRegion (lry) | int | always 0
xPixelAngle (xpa) | float | The maximum angle subtended in X or Y by a single pixel