int hedge_primary(<geometry>geometry, int hedge)
Each class of equivalent half-edges has precisely one primary half-edge. In particular, a half-edge which is equivalent to no other half-edges is always primary. Primary half-edges are useful for accounting for each edge exactly once as each edge may be realized by any number of equivalent half-edges.
When running in the context of a node (such as a wrangle SOP), this argument can be an integer representing the input number (starting at 0) to read the geometry from.
Alternatively, the argument can be a string specifying a geometry file (for example, a
.bgeo) to read from. When running inside Houdini, this can be an
The primary half-edge
hedge that shares the source and destination of
hedge (possibly in reverse order).
-1 if the half-edge is not valid.
int primhedge; // Get the primary half-edge equivalent to half-edge number 3. primhedge = hedge_primary("defgeo.bgeo", 3);