Primitive Variables

identifier:object

string

empty

Object shape name.

derivatives:extrapolate

integer

1

Extrapolated smooth normals across grid boundaries.

displacement:ignorereferenceinstance

int

0

Indicates if displacement shading should ignore properties of the reference instance.

displacementbound:CoordinateSystem

string

object

The name of the coordinate system that the displacement bound is measured in.

displacementbound:offscreen

int

0

Apply 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:sphere

float

0

Maximum displacement distance used to compute object bounds. This value should be as tight as possible.

Ri:Orientation

string

outside

Geometry winding order that determines surface normal. This attribute effects lighting and displacement. Supported values: inside, outside.

trace:autobias

integer

1

Enable automatic raytrace bias.

trace:bias

float

0.01

Manual raytrace bias in object space. Small values should be used to avoid artifacts such as shadow acne.

trace:displacements

integer

1

Enable displacement shading.

dice:micropolygonlength

float

1

Micropolygon distance in raster space for "instanceprojection" dicing. Values are expressed in pixel size.

dice:offscreenstrategy

string

viewfrustumdistance

Dicing method of objects outside the viewing frustum. Supported values: viewfrustumdistance, worlddistance, objectdistance.

dice:rasterorient

integer

1

Changes micropolygon size according to the viewing angle of a surface. When rasterorient is on, surfaces are coarsely diced at a glancing angle.This feature is very useful for ground planes and other large objects that are seen at an angle and it should be disabled for geometry that is instanced several times as it can be seen from different angles as well as when displacement details are lost.

dice:referencecamera

string

empty

Specify the camera used for dicing. If no reference camera is specified, RenderMan will use the primary camera.

dice:referenceinstance

string

empty

Specify 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:strategy

string

instanceprojection

Dicing method of objects within the viewing frustum. Supported values: instanceprojection, worlddistance, objectdistance.

dice:worlddistancelength

float

-1

Micropolygon distance in world space for "worlddistance" dicing or object space for "objectdistance" dicing.

Ri:GeometricApproximationFocusFactor

float

0

Allows the renderer to use more coarse dicing for blurry objects due to depth of field.

falloffpower

float

0

For 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.

dice:minlength

float

-1

Volume minimum dice length. Negative indicates to automatically compute this value.

dice:minlengthspace

string

empty

Coordinate space of dice:minlength.

Ri:Bound

float[6]

0 0 0 0 0 0

Volume bounds.

volume:dsominmax

integer

0

dice:pretessellate

integer

1

Pre-tessellate subdivision geometry to polygons.

dice:watertight

integer

0

Tessellate geometry with no holes. Watertight geometry requires less raytrace bias.

shade:faceset

integer[n]

empty

Active geometry face indexes.

stitchbound:CoordinateSystem

string

empty

stitchbound:sphere

float

0

trimcurve:sense

string

inside

Supported values: inside, outside.

polygon:concave

integer

1

Allow concave polygons.

polygon:smoothdisplacement

integer

0

Output smoothed (per-vertex) normals as Ndsp primvar, if polygon:smoothnormals hasn't already inserted smooth normals.

polygon:smoothnormals

integer

0

Smooth (per-vertex) normals if not provided.

procedural:immediatesubdivide

integer

0

procedural:reentrant

integer

0