Mudbox for film, workflow?

[Dagwood]

Hi everybody!
I've been using maya and zbrush for a while now and thought it was about time to look into mudbox seeing as the polycount and interface are way cooler imo.

Anyway in the past when using displacement I've only used them for still images as they seem to be way to unpredictable for animation. When sculpting a head and bring it back in maya it looks all smooth and formless. All the characteristics are gone, but once you render with the displacement map it all comes back. How would you go about setting up blendshapes for a thing like this? And when animating when do you know if the hand is intersecting the body at some point until you render it?

I've been thinking about this for quite some time and really don't understand it. When animating a normal polysmooth character what you do is copy it and skin one version. The other is subdivided and split up and then parented to the different bones to get a representation of how thick or thin the mesh really is when rendered so you won't get a surprise. And this works well for cartoony characters like Ratatouille and Madagascar etc.

Is it a good method to do the same thing with your level 3 or level 4 mesh from zbrush?
Like you split this up to get a representation of the actual volume? But even so it seems it will be like 400 000 polys in your scene(may be exaggurating) and when dealing with multiple characters......

Perhaps you should do as much work you can on the mesh in maya and make it dense enough so it looks good when smoothed and then only extraxt a bump map from mudbox for extra minor details like skin pores, small wrinkles etc.

[Bryan Silva]

"Anyway in the past when using displacement I've only used them for still images as they seem to be way to unpredictable for animation."

This is only true when your displacement map is 'doing too much' for your mesh. FOr meshes that use displacement maps, but will also deform, you want to make sure that your low mesh that is in maya and being displaced, matches your end result (displaced mesh) as closely as possible in terms of shape. Im not saying that the poly counts have to be comparable. Rather that the displacement map should not be changing the shape of your mesh very much. It can slightly change the silhouette. Accent it a bit, however the more form that the displacement map carries, the higher risk you run of having your mesh behave incorrectly when deformed.

"When sculpting a head and bring it back in maya it looks all smooth and formless. All the characteristics are gone, but once you render with the displacement map it all comes back. How would you go about setting up blendshapes for a thing like this? And when animating when do you know if the hand is intersecting the body at some point until you render it?"

To have a better representation of what the rendered mesh will look like in the viewport you can use normal maps. However, these maps will not change the silhouette of your mesh, so they will not help an animator know when clipping will occur. For that reason also, it is very important for the deformable meshes in your scene that are being displaced to 'fit' your displaced mesh as closely as possible.

"Perhaps you should do as much work you can on the mesh in maya and make it dense enough so it looks good when smoothed and then only extraxt a bump map from mudbox for extra minor details like skin pores, small wrinkles etc."

The base displacement maps we used on characters in the feature I am wrapping up now were more like glorified bump maps than traditional displacement maps. Mudbox generated displacement maps were only used on the heads and hands. We even animated the opacity of a number of additional displacement used for expressions. This way we could counter some details like wrinkles that were in the base displacement map. So for instance lets say you have a character who is older and has crows feet wrinkles in his base displacement map. Well when he/she raises their eyebrows the crows feet should subside or completely be absent due to the skin getting tight in that area. This was a case where a new displacement map could be used to counter the details in your base displacement map. I hope that made sense.

[Dagwood]

Thanks alot for the thorough answer. Might just stick to normal maps for deformed characters.
Why would you need the extra geometry for crows feet? Wouldn't a bump map be sufficient for smaller wrinkles?
How does a general workflow look like in your case?

My biggest concern is that when modeling a base mesh in maya, then smoothing it, it looks great. Bringing it in mudbox and doing some sculpting and then exporting the level 1 mesh back in maya and smothing it, it just looks like a flat formless version of the original and with added normal map in this case it looks like shit anyway cause the whole silhouette is gone.

So perhaps this is the workflow you should be using for deformed characters:
1. Block up proportions in mudbox on a generic base mesh.
2. Retopologize it and add all the details you wish
3. export the level 2 or so(depending on how dense the mesh is)
4. Skin the level 2 and do all the blendshape for this one.
5. Use like level 3 and split up to parent each body part to the joint it's representing.