Ri for MEL
Ri for MEL
RenderMan for Maya has superb support for RenderMan Attribute and Option control based on Maya attributes. This "data-centric" support is fundamental to Maya's operation and offers advantages for file reference parameter animation and general orthogonality with Maya tools.
There are times where procedural control of RenderMan state is desirable. We offer this capability in RfM through a MEL binding to RenderMan Interface procedures. Whether rendering directly (internally) or to produce RIB, these new commands can be used to tailor the Ri stream via MEL procedures. New torattrs are supported to provide hooks for custom MEL procedures. These can be assigned to shape, light and transform nodes and will be executed when RfM is rendering.
defaultRiOptionsScript
Runs during rendering/ribgen and provides a hook to override rendering options via script control.
defaultRiAttributesScript
Runs during rendering/ribgen and provides a hook to override default rendering attributes via script control.
transformBeginScript
Runs during rendering/ribgen at each transform nodeimmediately following RiAttributeBegin.
postTransformScript
Runs during rendering/ribgen at each transform node immediately following the setup of the transformation state.
transformEndScript
Runs during rendering/ribgen at each transform nodeimmediately preceeding RiAttributeEnd.
preShapeScript
Runs during rendering/ribgen at each shape node immediatelypreceeding geometry output.
postShapeScript
Runs during rendering/ribgen at each shape node immediately following geometry output.
Ri Command Syntax
Ri commands fall into two broad syntactic classes: commands with and commands without variable length parameter lists. Those commands without variable length parameter lists generally accept typed, positional arguments following the RIB binding conventions. For example, a red color is specified this way:
RiColor 1.0 0.0 0.0
Since Ri parameter lists are comprised of a heterogeneity of types, we follow the Ri-convention that requires parameter-type declarations be provided. Modern practice combines the type declaration with the parameter name to produce an inline declaration.
Inline Declaration Syntax
"type name" ''value'' "type[arraylen] name" ''value1'' ... ''valueArrayLen''
Parameterlist Examples
RiAttribute "identifier" "string name" "myname"
RiAttribute "visibility" "int camera" 1 "int trace" 0
RiSurface "mySurfaceShader" "string[2] myFiles" "file one" "file two"
"float Ks" 1.0 "float[5] myweights" 1 2 3 4 5;
Scope
RiBegin filename_string
RiEnd
RiFrameBegin frame_int
RiFrameEnd
RiWorldBegin
RiWorldEnd
RiAttributeBegin
RiAttributeEnd
RiTransformBegin
RiTransformEnd
RiSolidBegin operation_string ("primitive", "intersection", "union", "difference")
RiSolidEnd
RiResourceBegin
RiResourceEnd
Options
RiOption namespace_string ...parameterlist... RiHider hidername_string ...parameterlist... - RiFormat xres_int yres_int pixelaspectratio_float RiPixelSamples xsamples_int ysamples_int RiScreenWindow left_float right_float bottom_float top_float RiCropWindow xmin_float xmax_float ymin_float ymax_float RiProjection projtype_string ...parameterlist... RiClipping near_float far_float RiDepthOfField fstop_float focallength_float focaldistance_float RiShutter min_float max_float - RiDisplayChannel channeldecl_string ...parameterlist... RiDisplay name_string type_string mode_string ...parameterlist... - RiRelativeDetail relativedetail_float
Attributes
RiAttribute namespace_string ...parameterlist... RiColor red_float green_float blue_float RiOpacity red_float green_float blue_float - RiSurface shadername_string ...parameterlist.. RiDisplacement shadername_string ...parameterlist.. RiAtmosphere shadername_string ...parameterlist.. RiInterior shadername_string ...parameterlist.. RiExterior shadername_string ...parameterlist.. - RiLightSource shadername_string lighthandle_string ...parameterlist... RiIlluminate lighthandle_string onoff_bool - RiShadingRate size_float RiGeometricApproximation type_string value_float - RiShadingInterpolation interp_string (smooth, constant) RiMatte onoff_bool - RiDetail minx maxx miny maxy minz maxy (floats) RiDetailRange minvisible lowertransition uppertransition maxvisible (floats) - RiSides sides_int (1 or 2) RiOrientation orientation_string (lh, rh, inside, outside) RiReverseOrientation - RiResource handle_string type_string ...parameterlist...
Transform
RiIdentity RiRotate angle dx dy dz (floats) RiScale sx sy sz (floats) RiSkew angle dx1 dy1 dz1 dx2 dy2 dz2 (floats) RiTranslate x y z (floats) RiCoordinateSystem coordsysname_string RiScopedCoordinateSystem coordsysname_string
Geometry
RiSphere radius zmin zmax angle ...parameterlist... - RiProcedural (work only with RIB out) RiProcedural "DelayedReadArchive" filename xmin xmax ymin ymax zmin zmax RiProcedural "DynamicLoad" dsoname xmin xmax ymin ymax zmin zmax ...paramlist...