Houdini 16.5 Geometry

Points and vertices

See how to edit points.

A point is simply a point in space as defined by four numbers (X, Y, Z, W).

A vertex is a reference to a point. Primitives use vertices to reference points. For example, the corners of a polygon, the center of a sphere, or a control vertex of a spline curve.

Primitives can share points, while vertices are unique to a primitive.

For example, you can have polygons that have corners at an identical location in space. The polygons may share a single point, in which case each polygon’s vertex at that corner would be a reference to the same point. Or, those vertices may each point to unique points that happen to have the same spacial location.

This is not merely an academic distinction. Unique-ing the points (giving each vertex its own point instead of sharing points at shared corners) with the Facet SOP has several important effects on polygons:

Similarly to unique-ing all points, you can use the Facet SOP to cusp polygons, unique-ing points selectively based on the angle at which the shared edges meet.




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