aRtBee, thank you so much for sharing your experience and your insight. You are really helping me understand this stuff.  Yes, DPH and I fell into the quad trap, I probably led him astray, because I was overconfident. Also the little well-meaning tutorials about how you can adapt conforming clothing to the cloth room and quickly set up something as a hybrid. That is what we tried to do. It seems that is the road to frustration.

We tried an alternative skirt from Freestuff, made for Sydney. Just a cone with the top removed and made of small triangles. One run of the cloth sim for me with default settings, with the same settee and pose on Dave's Esther, and a perfect drape first time. No poke-through, no strange behaviour, and the preview consistent with the simulation results. Just one row of polys constrained around the waist and it didn't fall off. I think there is a lesson there. We are re-thinking the wardrobe for our story now. Fortunately David has awesome modelling skills, so we can fix meshes and triangulate them if needed.

What I don't understand is why during the simulation I got an almost perfect drape in preview with the original dress, and at the end, even if I step back to earlier frames, I get a totally different disaster. Surely that is a bug in the cloth room? It just seems wrong.

Poser 11 Pro, Windows 10

Auxiliary Apps: Blender 2.79, Vue Complete 2016, Genetica 4 Pro, Gliftex 11 Pro, CorelDraw Suite X6, Comic Life 2, Project Dogwaffle Howler 8, Stitch Witch