We use GeometryInput in the C API to create geometry, as other methods are too slow.
But now we would like to set the Cast Shadow flag on edges. The issue is that there are no functions to set that flag on edges in a GeometryInput.
We need to do another pass one the Entities collection once it’s been filled with the GeometryInput, and cast Edges to DrawingElements, on which we can set the flag. But I don’t know how to keep track of the edges between the GeometryInput and the Entities collection. Any idea how I can identify them?
If you don’t need to set hidden edges, you could use that to mark the edges and do a post-pass.
I do something similar with SUbD - only with the Ruby API’s Geom::PolygonMesh. I use negative indices to mark the diagonals, then a post-pass to correct the properties.