In the top panel, you can see that from a side view, the two arms don’t exactly line up. The bottom panel shows the arms properly mirrored.

Symmetry
Having a symmetrical model is extremely important. Symmetry helps everyone in the character pipeline, from the modeler to the texture painter to the character TD. Knowing that one side is identical to the other is a great timesaver. The benefits of symmetry for the character TD include the ability to duplicate across a chosen axis or mirror. Joints and rigging systems are easily mirrored, which saves a lot of the character TD’s time. Mirrored skin weighting reduces the amount of point weighting that is needed on the geometry. If you want to get really sophisticated, you can even create scripts that will mirror the complete character rig. Sometimes models get rushed through the modeling portion of the production pipeline. This can result in a model that is slightly shifted, or is not mirrored; check for these problems before you spend any time rigging or skinning your character. If there are problems, make sure you let people know the cause for your concern and what should be fixed. If you’re working alone, make sure you spend the time looking for issues related to asymmetry — you’ll hate yourself later in the process if you allow for any asymmetry in a model.

However, you may want to introduce slight asymmetry into the model so that it doesn’t have that perfect CG look. Isolate the asymmetrical modeling to the areas where it will be noticed, such as the face, and try to avoid it in the arms and hands. A common way to add asymmetry into a model is to introduce deformers and blend shapes after it has been set up.

If you’re constructing the geometry, you can only blame yourself for not doing your homework if something is built incorrectly. You must plan ahead and take the time to make the changes that are necessary. If you aren’t the modeler, the sooner you are involved in the modeling process, the better your setup will turn out.

To learn more about Smooth Skinning deformers, the process of analyzing storyboards and other topics of interest to animators, check out Inspired 3D Character Setup by Michael Ford and Alan Lehman, series edited by Kyle Clark and Michael Ford: Boston, MA: Premier Press, 2002. 268 pages with illustrations. ISBN: 1-931841-51-9 (US $59.99). Read more about all four titles in the Inspired series and check back to VFXWorld frequently to read new excerpts.

Alan Lehman (left), Michael Ford (center) and Kyle Clark.

Author Alan Lehman, an alumnus of the Architecture School at Pratt Institute, is currently a technical animator at Sony Pictures Imageworks, as well as a directed studies advisor in the Animation Studies Program at USC's School of Cinema-Television.

Series editor and author Michael Ford is a senior technical animator at Sony Pictures Imageworks and co-founder of Animation Foundation. A graduate of UCLA’s School of Design, he has since worked on numerous feature and commercial projects at ILM, Centropolis FX and Digital Magic. He has lectured at the UCLA School of Design, USC, DeAnza College and San Francisco Academy of Art College.

Series editor Kyle Clark is a lead animator at Microsoft's Digital Anvil Studios and co-founder of Animation Foundation. He majored in Film, Video and Computer Animation at USC and has since worked on a number of feature, commercial and game projects. He has also taught at various schools including San Francisco Academy of Art College, San Francisco State University, UCLA School of Design and Texas A&M University.