Eeeek, just realised that I gave the wrong value to the RAY_CLOSEST_HIT flag. In ode/src/collision_kernel.h it should be defined as: RAY_CLOSEST_HIT = 0x40000 Otherwise RAY_FIRSTCONTACT | RAY_BACKFACECULL == RAY_CLOSEST_HIT which wasn't quite my intention :) > vadim, i've checked in your trimesh-ray / dGeomRay*ClosestHit() patch. > thanks. > > russ.