TYPE: SOP
TITLE: Subdivide SOP

Subdivide evaluates a Creased Uniform Rational Subdivision Surface, or a 
CURSS.  It does this by applying a Catmull-Clark subdivision to a polygon 
network with semi-sharp creases.  While the topology of the input mesh can 
be arbitrary, for best results all polygons should be convex and relatively
uniform in distribution.

All polygons in the left input which are specified by the "Group"
field are used to determine the polygon mesh to subdivide.  For
polygon edges to be classified as the same edge, they must share the
same points.  Merely being physically close is not sufficient.

The elements of the right input specified by the "Creases" field are
used as creases.  Each edge in a crease polygon corresponds to the
edge in the polygon mesh which has the same point numbers.  Again,
point position is irrelevant.

Parameters:

    Group              - Subset to use as a polygonal mesh and subdivide 
    Creases            - Subset (of right input) to use as creases
    Depth              - How many iterations to subdivide, higher numbers 
                         give a smoother surface.                   /iterations
    Override Crease Weight Attribute - Determine if the crease sharpness should 
                         be determined by the primitive or vertex
                         "creaseweight" attribute or by overridden by this
                         operation.                             /overridecrease
    Crease Weight      - If the crease weight is overriden, this is the 
                         weight used.                             /creaseweight
    Generate Resulting Creases - If the creases are sharper than the depth, 
                         some will still be present in the final geometry.  
                         This option determines if they will be present in 
                         the resulting geometry.                 /outputcrease
    New Group          - Name of the group to place all generated
                         creases into.                          /outcreasegroup
    Pull Cracks Closed - Move points on boundary of subdivided area in order
                         to close cracks formed during the subdivision.
    Bias               - Determines which points are moved when pulling cracks
                         closed.                                          /bias
	0 - Means move points on subdivided area to meet
	    boundary.
	1 - Means move points on boundary to meet subdivided
	    area.
    Stitch Cracks Together - Add polygons to close the cracks caused by
                            subdividing.
    Divide Boundary Edges  - Whether or not to divide edges surrounding
                            subdivided area when pulling or stitching cracks.
    Recompute Point Normals - Re-evaluates point normals if they
			    exist.  If this is not set, the point
			    normals will be interpolated in the same
			    manner as the points.
    Smooth Vertex Attributes - If on, vertex attributes will be
		smoothed in the same manner as the point attributes.
		However, vertex attributes at seams (places where
		points meet but the vertex attributes differ) will
		still be linearly interpolated.  If off, the vertex
		attributes will be linearly interpolated.  To match
		the Mantra subdivision rendering, this should be set
		to off.

See also: Divide, Smooth, Crease
