Fallout 3: armour rigging(?) problem

[JW1]

I wonder if anyone has come across this problem/knows a solution?

I found a model on the internet (.obj) that I decided to try to convert into a piece of armour. I got it into Blender and converted it to .nif without any problems. I then weighted it to skeleton.nif, using bone heats. The resulting mesh surprisingly deforms rather well and works in the game.

The problem is this: it's impossible to import the mesh back into Blender. The import script fails with the message "ZeroDivisionError: cannot invert matrix" followed by a 4x4 matrix of numbers.

I've tried multiple times weighting the mesh in different ways and with different skeletons, but the result is always the same: the mesh works in the game but I can't re-import it to work on it.

Does anyone know what's causing this problem?

[motarx]

Have you used 'the force' option? No idea what causes it, but I've noticed I get this on complex meshes that work fine. If not maybe you could try poking at it with nifscope.