Normal map baking: Heads with open mouths. How to?

[East]

When you guys bake normal maps for a head, and the final character is supposed to have an emotable open mouth, do you model the high polygon source model with an open mouth? Or do you model it with the mouth closed, bake, and then afterwards "cut" the mouth up, and adjust the normal map accordingly?

I've been experimenting with both a bit, and have had some mixed results. To get a good result with an open mouth high polygon source I have to bake the normal map with the mouth pretty much wide open to avoid pinching at the corners.

So out of curiosity, how do you guys handle this?

[Snowfly]

Editing the normal map in Photoshop, but only because I don't rely on the bake for everything. It's just a small area worth of pixels anyway, and not that complex.

[East]

I guess it all boils down to how good you are at editing normal maps by hand /images/graemlins/smile.gif It is definitely a skill I need to work on.

[Eric Chadwick]

I'd try casting the outside separate from the inside top separate the from inside bottom... baking each low-poly area independently of the others. In 3dsmax you can set the Projection to only hit the matching material ID.

[Ruz]

I am veering towards mouth closed and cut open after. seems the most hassle free solution for me anyway

[almighty_gir]

i model the mouth attatched to the model, in a closed position, then remove the entire mouth, invert the polygons, and bake.

when i've baked, i invert the polies again, and flip the appropriate normalmap RGB channels, and attatch the mouth again. works fine, with minimal hassle (really how hard is it to select a group of polies and click detach).

[Snowfly]

[ QUOTE ]
I guess it all boils down to how good you are at editing normal maps by hand /images/graemlins/smile.gif It is definitely a skill I need to work on.

[/ QUOTE ]

imo everyone should get their hands dirty with hand editing normal maps at least once or ten. but it's a good question. :-)