Hello everyone ! So I'm experimenting many issues with my mesh works since the very beginning (august 2011), I hope someone will be able to enlighten me in here ! 90% of my mesh uploads have random glitches such as missing/untextured faces. The most annoying is that I can reupload the exact same fil three times in a row, the glitches will be somewhere else on the mesh and even with some luck, the mesh can magically appear flawless (still using the same file without editing it). I feel like playing lottery each time I upload something, since flaws are never displayed in the preview window. Here is a sample : First upload : there is a flaw behind my model, front is ok. http://i43.tinypic.com/2gx3das.jpg Second upload, same file (I deleted the previous *.slm in the folder) a hole appeared on the torso, texture glitch on the back : http://i40.tinypic.com/qx5kjr.jpg Third upload, same file, (deleted *.slm as well) everything's good : http://i44.tinypic.com/166ao41.jpg What I'm using : Blender 2.59 64bits (tried 32 bits didn't work any better), tried both Blender collada export/SL collada plugins. Jass/Blender 2.49 collada 1.4 not working either. SL viewer 3.2.5, but I tried several builds and viewers, still having the issue. My mesh is made of 14000 triangles (7000 quads). What I tried, and what i'm aware of : The normals are all facing the right side (checked and rechecked them with blender display), I recalculated outside, applied scale/rotation. All my vertices belong to bone groups and I don't have any 0 weighted vertex (checked with 2.49 clean meshesscript/check for unweighted vertices). I don't have any double vertices. I'm using avatars.blend from standard sizing package provided by Lelutka/Mon tissu http://dl.dropbox.com/u/6003454/Standard%205%20sizes.zip wich are working great for other designers. I also tried to convert my quads to triangles before importing it to SL (since it looks like SL viewer is unable to convert my mesh correcly), the two uploads after were flawless, then the glitches came back on the third upload. I rigged my mesh using the 2.49 bone weight copy script and some manual blur and it moves correclty with the skeletton. I still think the trouble is coming from my mesh, maybe the way I modelized/rigged it but I'm running out of ideas for now :( Thanks for reading, waiting for your feedback, any idea is more than welcome !