I’ve discovered an issue with the Multiple-Edgeloops setting that does not exist in the Single-Edgeloop setting.
(I have it set restricted to a Polyloop.)
I have a mesh where I generated thickness using PolyLoops. In the toe of the character is a bit of a mess of inter-penetrating geometry due to this operation, but that is not the issue.
If I Insert using Single-Edgeloops to add divisions to a Polyloop I need them in, I can then “Reconstruct Subdiv” without issues.
But, if I use the Multiple-Edgeloops setting to insert the same amount of loops, then try to Reconstruct Subdiv, it tells me there are triangles, despite the topology looking the same…
I noticed when I use the Multiple-Edgeloops tool, the whole surface of the mesh changes in shading ever so slightly, but this does not happen when using the Single-Edgeloop tool. So for some reason Multiple-Edgeloops is processing the whole mesh instead of just the polyloop.
I took the Multiple-Edgeloop affected model into Maya, isolated triangles, and noticed the triangles were created in the toe section of the mesh, where the geometry was a bit jumbled.
I tried reproducing the issue on lower poly meshes but couldn’t. So here is an example file. The thickness on both were created using PanelLoops.
http://www.mediafire.com/download/bpv3do92i6dgjnp/InsertMultipleBug.ZTL
To reproduce the issue, you can apply a PanelLoops to the single-sided mesh and then insert 3 edge-loops along the thickness polyloop using Multi-Edgeloops. Then try to Reconstruct Subdivs.