Quote - I do understand the renderer turns anything into tris, we still aren't sure about the sim routine, do we? 

Whoops - where did that come from? We have evidence that the renderer does not turn mesh polygons into tris. The evidence (and documentation of REYES) says the renderer divides every polygon into micro polygons, forming a mesh within the mesh. A twisted quad becomes a submesh of tiny polygons, forming a membrane attached to the original polygon vertices. This membrane also has a mesh structure, but I don't think they are triangles - I think they are quads but I don't know.

So in Poser each mesh polygon, even a triangle, becomes subdivided into micro-polygons, usually hundreds to thousands of them to form a membrane. To say that it triangulates is vastly misleading. Certainly a simple quad is not divided into two triangles.

As for the simulator - if we suppose it divides the quads into two triangles and proceeds from there, it would seem to be possible for me to generate triangles explicitly, in various configurations, and run simulations of each and compare against the quad simulation. The one that matches should reveal how the quad simulation is triangulated. So far, none of the configurations I've tried match the quad simulation AT ALL. The implication is that the cloth sim is not triangulating quads - it is doing something else.

 

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Renderosity forum reply notifications are wonky. If I read a follow-up in a thread, but I don't myself reply, then notifications no longer happen AT ALL on that thread. So if I seem to be ignoring a question, that's why. (Updated September 23, 2019)