Mesh Preparation for Rigging/Skinning

Rigging
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#1

Heya,

I’m a technical animator, and I’m preparing an artist workshop for mesh prep for rigging/skinning/animation.

Since I think there are a lot of different approached and opinions and there is no right or wrong. I was wondering if you guys have could share what your guidelines are for artists for mesh prep. Specifically with various armour types that have metal pieces, fabrics and skin underneath, and our setup currently doesnt allow for proper fabric physics.

We want to assume:

  • AAA/AA/Realistic or as close to in quality (so no toon for example)

So some things I would say for example are:

  • complexity in the wrist/shoulder/hip areas need to be reduced
  • vertexes that are not merged, only combined should be close together to avoid clipping, specifically for armour pieces that have fabric below metal bits
  • there should be no holes visiable from the outside of the mesh
  • polygons inside the mesh that are not visible need to be deleted
  • (because of no physics), I would avoid having seperate mesh pieces on top of each other, and instead extrude where possible to get the same result.
  • normal maps are preferable to vertex displacement for texture details where possible.

Open questions I have:

  • does anyone else have a non-physics workflow for checking meshes. Especially in the skirt region there are usually some very ugly deformations. Also limitations due to a shared rig for example where joint placement isnt always ideal.
  • at which point do you fix it yourself vs send it back to character art
  • combined seperated meshes vs merged meshes (merged assuming vertices are stitched together)
  • accepted unrealistic deformation (for example metal plates bending) to get a better overall look, vs. sticking to realistic deformation which often causes clipping.

In general I just wanted to have a discussion with other tech anims who may have the same headache trying to find cohesive industry standard info out there.

#2

Standards for games vs film will differ. You said “AAA” so I’ll speak to games. Many of the questions will also depend on the specific game engine and exporter tools.

In the old days, and at smaller studios, modeling would hand off stuff and tech art did the manual work to get it ready for the engine. Now, our studio is very strict about model handoffs to rigging.

We enforce a contract with the modeling department that they maintain a “master” Maya file that is the latest version of the model, ready for rigging. If there are problems we kick it back to Modeling to fix. For quick fixes, we may update the master and inform Modeling, expecting changes to remain in future updates.

We provide Modeling with Maya tools that automate checking for stuff like:

  • Valid mesh Names
  • Zero / Frozen Transforms
  • No Pivot Offsets
  • No Construction History
  • No Custom Attributes
  • No N-gons (tris and quads only)
  • No illegal-for-the-engine geo like lamina faces etc

we also have a test exporter tool that skins to a single test joint and exports a test game asset. Modeling is expected to confirm the mesh displays correctly in engine before passing to rigging.

Character posing is something we often push back on. Things like Feet pointing straight, IK limbs being co planar, stuff that helps our rigging tools work better.

This arrangement took plenty of work and buy -in, but it avoids the pain and cost of iteration tremendously.

3 Likes
#3

Thank you for the extensive feedback Definitely some great info. Much appreciated