estherau; I'd have to run some specific tests, but I'm 98% certain that as long as an item is listed in the heirarchy tree, while it may not be 'visible', it is still there as far as collision detection is concerned (the visibility option doesn't make the mesh section go away; it just nullifies the scanline return on it. The actual polygons are still there). I'm assuming that the pants mentioned are conforming; this opens up one potentially hellatious can of worms. I =think= I've seen a couple of instances where there was, for lack of a better term, 'crosstalk' between the character mesh and a conforming cloth peice, and for the same reasons; the part names are identical. If the cloth is going to be touching those pants, then make them visible, turn on collision detection for the parts that the cloth will possibly touch, and turn =off= the detection on the actual character for those same parts. Conforming clothing is a character wrapped around a character, so the only thing that should be a collision surface is the outermost 'character'. Whatever is under it shouldn't be enabled as a collider; that may even be the problem. When collision detection is turned on, then the object being collided against is involved in the simulation,and subject to the same fubars as the cloth is. Two characters interpentrating, like say at a bending joint, -could- trigger a collision error in itself. Not with the cloth, but generating something like a divide by zero error due to two surfaces being defined as 'solid' having penetrated each other. Then there's the fact that many of the conforming items are dynamic cloth death traps. Dynamic cloth is a simply polygon sheet; a lot of the conforming clothes out there are multiple layered, have polygons folding back on themselves, varying types of polygon, etc... =ANYTHING= that breaks the collision rules can, and usually does, either stop the simulation, or lock it into a repeating loop (usually the divide by zero error). I fought with one sim for 2 weeks, gave up, and went on. A couple of months after that, I was bored and loaded it, and found the issue immediately. It was a belt buckle that was attached to the cloth item, but it had a listing as a seperate prop in the heirarchy tree. Once I turned collision on for that, the sim ran correctly.