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From Odwiki

What it does

In Houdini, one often uses shared points to define topological information. Thus, two quadrilaterals may share points along an edge. Both quadrilaterals may, however, have different shaders assigned to them. If one was do an operation that would merge the quadrilaterals into a single primitive (such as the TriStripSOP), these shared points would result in the quadrilaterals being turned into a single primitive, and hence, a single shader.

The PrimitiveSplitSOP, when given an attribute and tolerance, will unique points that are shared by two primitives who differ in that attribute.

If one wanted to ensure a TriStripSOP does not merge differing shaders, use a PrimitiveSplitSOP with the attribute set to the shader attribute. Example

1. Default GridSOP
2. Append a PrimitiveSOP
   • Source Group, set to 1-50
   • Attributes Tab, set the Color menu to Add Color
   • Attributes Tab, set the color to Red (1, 0, 0)
3. Append a TriStripSOP
   • You will note that the colour region has been lost.
4. Insert before the TriStripSOP a PrimitiveSplitSOP
   • Attribute, set to Cd

You will now note that the colour scheme has been maintained. Turn on PointNumberDisplay to see the doubled points.

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