geometric operations

Attributes

(color vec3)
(color r g b)

(opacity vec3)
(opacity r g b)

color and opacity specify color and opacity as a red, green, blue triple stored in a vec3 or as individual floating point numbers. Each component should be a value between 0 and 1. In the default graphics state, the color is white, #<1 1 1>, and the opacity is fully opaque, also #<1 1 1>.

(surface name paramlist)
(atmosphere name paramlist)
(displacement name paramlist)
(interior name paramlist)
(exterior name paramlist)
(deformation name paramlist)

These procedures specify shaders for the corresponding types. name should be a string corresponding to the name of the shader to use.

(identifier type name)

Allows a logical identifier name of a particular type to be associated with subsequently created gprims/gops. name is a string and type is a symbol.

(basis type)
(basis matrix step)
(basis umatrix ustep vmatrix vstep)

basis specifies the basis function(s) which will be used by subsequent bicubic surface patches. The first form is the simplest and only requires that you specify the "type" of basis. type is a string and should be one of "bezier," "bspline," "catmullrom" or "hermite." The second form of basis specifies an arbitrary basis matrix (a mat4) and a step (an integer) for piecewise bicubic patch meshes. The third form specifies independent basis matrices for the u and v parametric directions on the surface.

(divisions udiv)
(divisions udiv vdiv)

divisions controls the quality at which continous geometry (splines and patches) is represented. udiv and vdiv specify the rate at which subdivision occurs along the parametric u and possibly v definitions of the object. If vdiv is not specified, it equivalent to udiv. The default value for both udiv and vdiv is 10.

(trim-curve ncurves order knot min max n u v w)

See The RenderMan Companion for a description.

(motion-blur onoff)

This gop and the motion blur facilities in AL are documented in the rendering section.