making a blendshape out of an imported model
 

Hi, I read that you can make a blendshape without duplicating from the original model.
I've already skinned a model and found that I can't detach a bit of skin and reattach it because it asks me to put it back to bind pose, which I can't do because it's already fully rigged with IKs and everything.

So in order to avoid this, I have imported a previous unbound model and used it as a blend shape. But it also adds some extra unpredicted deformations along with the desired deformation. I deleted history and everything from the imported model and they have the same number of vertices and everything.

So am I missing something?

Blending works with the polygon vertices. For the process to work, you need to have blend shapes and a blend target that are identically numbered. I have read that Maya 8 lets you do blends with dissimiliar models but I've never tried it. If your bound model and your newly imported model are having problems with blends then they don't have the same numbering. Maybe you added more edge loops to your bound model... I can tell you that if you export your model as an obj then import it back into Maya, the vertices numbering will be changed. I don't know if you are importing an obj copy of your model or if you are importing the Maya Binary (.mb) file but only the .mb will work, assuming the vertices between the bound model and the imported model are the same.

As far as unbinding your model. You should turn your IKs off then return your model to the bind pose. If you don't know how to get back to the bind pose then you probably didn't rig your model correctly. It should be as easy as setting your control objects' rotation and translation values back to zero.

Hey Thanks, but i managed to work it out. I didn't even know you could turn off IKs.. =S

I'll post this up for the benefit of other newbies... to show that it's not the end of the world when you happen to skin your character BEFORE adding blendshapes.
I knew about how blendshapes must have the same number of vertices as the original model.

So what I ended up just doing was saving a copy of the file, unbinding the head surface, deleting everything else but the surface and then importing this file into my current file.

It's also good to note that the imported file should be centre pivoted, i.e. at the same coordinate as the original model. I found that if the imported model was off the centre, the deformations screwed up for some reason.

Anyway, hope this helps!