Characters - Quick question about mouth bags...
polycounter lvl 5
Hi
What's typically done first - adding a mouth bag to the low poly and then do the baking? Or do the baking first and then add a mouth bag?
I figured it was best to do it afterwards as the high poly probably won't have one, which may give it some weird baking issues...? But then, doing it after, once all the baking is done, will kinda screw up some of the UVs (mainly the head) as you end up created new geometry that will need to be cut away and added somewhere (if there's any space left).
Thanks
Replies
if the mouth is animated, i create it from the start. i sometimes reuse teeth and tongue, useful to have in your morgue kit. i place the teeth/gums and create the mouth bag around them at blockout/sculpt, giving most attention to the inner lips.
Yeah, I'll be posing the mouth into a smile with it slightly open, so you can see the teeth and tongue. Or at least a bit of them.
I do the highpoly with the mouth open. Separate top and separate bottom teeth and separate tongue. Lowpoly the same. Never had a problem with the inside of the mouth uvs but marmoset puts the lowpoly in a cage automatically and separating meshes into baking sets allows baking in one operation without anomalies.
So, do character artists typically make the mouth bag with the high poly then? I've had to make some refinements to my low poly, and the version of the mesh I'm using now has the mouth bag made, however it produces a weird baking issue on the bottom lip. No doubt because there's no matching geometry. Is there anything that can be done to prevent this? I suppose I could always paint out the issue from the Normal map, but was just wondering if there were any other things I could do. I will need to add a bit of a chamfer to the edge of the bottom lip leading into the mouth bag too as it's currently too sharp, but I don't suppose that would sort it, right?
Thanks
this looks like the cage of the lower lip clipping into the upper lip and capturing that.
usually this is avoided by a slightly opened mouth for baking
Huh. Hmm. Thing is, when I baked before, before I added a mouth bag that is, this problem didn’t happen. And the lips are sliiiightly apart since adding the mouth bag. You have to zoom in very close to that area to be able to notice though.
Looks like the issue is occuring on the AO map, not the Normal like I thought. I'll try opening the mouth a little though, see what that does.
Well, alright! Looks like opening the mouth did help. Along with setting the Occlusion parameters so Ignore Backfaces is set to By Mesh Name and Self Occlusion is set to Always. :D
Thanks for the suggestion. :)
Okay, I'm a bit stuck and unsure... Is it not possible to bake a Normal map for a character and then adjust the mesh for a pose/animation...? I always thought this was something you can do. :-\
I've baked mine with a neutral/a-pose and expression, but for the rig/pose, I want the character's mouth open a bit. Unfortunately, the corner of the mouth looks like a mess. :(
Here's the low poly in Max with the lower mouth slightly open:
The bake in Substance Painter:
And then with the mouth open after posing in Marmoset. The Normal map is showing an obvious pinch in the corner:
What would be the best solution here? And what should I make sure to do in future with the high/low poly?
Thanks
arrange your mesh for clean bake results, splay arms, legs, fingers, eyelids closed, mouth open, then straighten these elements afterward with a new mesh to hand off to a rigger. keep both in your source scene so you can revisit/polish the model down the road.
Yep, as someone who rigs up a lot of characters, I totally agree and really appreciate this, especially the closed or half closed eyelids. I really hate dirty/smeary eyelids because we're stretching a tiny handful of pixel creases when a character blinks.
Your rigging pose does not need to be your bake pose and this a great way to get good looking bakes and mitigate squashed details that stretch poorly.
It can help to have a rough proxy character in your scenes that you can wrap your model to and morph/blendshape/bone deform the proxy mesh into the different poses. It's good for doing iterations and edits on geo, or just good for standing up new characters of similar shape and size. Bonus points if it gets you a jumpstart on skinning a character.