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These may also be referred to as "master attributes" for clarity versus Instance Attributes which may be varied per instance.

Common

Name
Type
Default
Description
identifier:objectstringemptyObject shape name.

Shading

Name
Type
Default
Description
derivatives:extrapolateinteger1Extrapolated smooth normals across grid boundaries.
displacement:ignorereferenceinstanceint0Indicates if displacement shading should ignore properties of the reference instance.
displacementbound:CoordinateSystemstringobjectThe name of the coordinate system that the displacement bound is measured in.
displacementbound:offscreenint0Apply displacementbound to offscreen geometry when dicing. Geometry that is entirely offscreen, but displaces into view may be prone to undertessellation because of the offscreen dicing strategy. This can be corrected by enabling this control and setting a reasonable displacementbound. Doing so will incur a performance penalty commensurate with the size of the displacement bound.
displacementbound:spherefloat0Maximum displacement distance used to compute object bounds. This value should be as tight as possible.
Ri:OrientationstringoutsideGeometry winding order that determines surface normal. This attribute effects lighting and displacement. Supported values: inside, outside.
trace:autobiasinteger1Enable automatic raytrace bias.
trace:biasfloat0.01Manual raytrace bias in object space. Small values should be used to avoid artifacts such as shadow acne.
trace:displacementsinteger1Enable displacement shading.

Dicing

Name
Type
Default
Description
dice:micropolygonlengthfloat1Micropolygon distance in raster space for "instanceprojection" dicing. Values are expressed in pixel size.
dice:offscreenstrategystringviewfrustumdistanceDicing method of objects outside the viewing frustum. Supported values: viewfrustumdistance, worlddistance, objectdistance.
dice:rasterorientinteger1Turning this off enables non-oriented dicing, a mode of dicing that computes micropolygon sizes using non-oriented raster space rather than screen-aligned raster space. Non-oriented dicing is useful for displacement around edges where projected micropolygon distance can be arbitrarily small.
dice:referencecamerastringemptySpecify the camera used for dicing. If no reference camera is specified, RenderMan will use the primary camera.
dice:referenceinstancestringemptySpecify the reference instance used for dicing and displacement shading. The reference instance is used to drive dicing and displacement based on its position, scale, user attributes, and scoped coordinate systems. Reference instances are specified by its identifier:name attribute (instance name). If no reference instance is specified, RenderMan will automatically pick the nearest instance inside the primary camera's view frustum.
dice:strategystringinstanceprojectionDicing method of objects within the viewing frustum. Supported values: instanceprojection, worlddistance, objectdistance.
dice:worlddistancelengthfloat-1Micropolygon distance in world space for "worlddistance" dicing or object space for "objectdistance" dicing.
Ri:GeometricApproximationFocusFactorfloat0Allows the renderer to use more coarse dicing for blurry objects due to depth of field.
Ri:GeometricApproximationMotionFactorfloat0Allows the renderer to use more coarse dicing for blurry objects due to motion blur.

Points

Name
Type
Default
Description
falloffpowerfloat0For use with points, if not supplied, or set to zero, the points will have a hard edge. A value of 1 is a "reasonable" value that emulates the usual cosine based falloff; this will likely be the goto value for most people doing volumetric particle effects. Values between 0 and 1 makes the falloff faster, eroding the point faster - point has "less presence". Values higher than 1 (up to infinity) makes the falloff slower to the point of being non-existent.

Curves

Name
Type
Default
Description
curve:opacitysamplesint0number of opacity/presence shading samples along a curve for opacity caching, if equal to zero then the value is determined using the dicing oracle and the lenght of each curve.

Volume

Name
Type
Default
Description
dice:minlengthfloat-1Volume minimum dice length. Negative indicates to automatically compute this value.
dice:minlengthspacestringemptyCoordinate space of dice:minlength.
Ri:Boundfloat[6]0 0 0 0 0 0Volume bounds.
volume:dsominmaxinteger0

SubdivisionMesh

Name
Type
Default
Description
dice:pretessellateinteger1Pre-tessellate subdivision geometry to polygons.
dice:watertightinteger0Tessellate geometry with no holes. Watertight geometry requires less raytrace bias.
shade:facesetinteger[n]emptyActive geometry face indexes.
stitchbound:CoordinateSystemstringempty
stitchbound:spherefloat0

NuPatch

Name
Type
Default
Description
trimcurve:sensestringinsideSupported values: inside, outside.

PolygonMesh

Name
Type
Default
Description
polygon:concaveinteger1Allow concave polygons.
polygon:smoothdisplacementinteger0Output smoothed (per-vertex) normals as Ndsp primvar, if polygon:smoothnormals hasn't already inserted smooth normals.
polygon:smoothnormalsinteger0Smooth (per-vertex) normals if not provided.

Procedural

Name
Type
Default
Description
procedural:immediatesubdivideinteger0
procedural:reentrantinteger0