Wrinkled model (normals?) Learning to model with Blender. Trying to modify an existing model, at some point I "wrinkled" it. I'm suspicious about some custom code (I'm developing a Blender plugin to export/import models from a game) to save and reload normals, but the case is I have this model now and I want to know what's going on so I can fix it.

With autosmooth turned off:



With autosmooth on:



What causes this? How can I fix it so when autosmooth is enabled, it looks like the figure on top?
Well, I found out that Reset Vectors in the Normals menu (Alt-N) seems to be the answer (you need to select all your vertices):



The result:



I don't know what I'm doing in my export/import code (that I mentioned above) but that's another story.