Sometimes all you want to do is dance – through your character, anyway- and not get bogged down in details about bones, constraints or modeling. MotionBuilder is a 3D character animation tool that allows an artist to focus purely on animation. It’s not for modeling, rigging or texturing- Autodesk expects you to use 3ds Max or Maya (or any other 3D app that supports the FBX file format). It’s not cheap, but time is money, and MotionBuilder is built to save lots of it.

MotionBuilder accomplishes this with a straightforward workflow revolving around the FBX file format and FBX plug-in, which get installed into your primary 3D application. This means you can export a model from your 3D app of choice and import it to MotionBuilder, where it then gets rigged and animated. When the animation is done in MotionBuilder, you export from there and import back into the 3D app and render. There are some protocols to follow to ensure the import/export process goes smoothly- bone naming conventions, etc.- but these are well-documented in MotionBuilder’s help files.

This is the first major release of MotionBuilder since Autodesk acquired Alias, and version 7.5 offers some important new features. Apparently, Autodesk thinks it’s a new release and not an upgrade, because there’s no upgrade price for 7.0 owners. While the new features and improvements are welcome, upgrading is really a judgment call for the artist. One must weigh the cost against the worth of the new features.

MotionBuilder was originally built for biped characters, but 7.5 now includes support for inverse-bending knees and elbows (think birds and dinosaurs). Additionally, improvements to the constraint and keyframe systems provide the animator with greater control and support for characters with more than two legs or arms. These improvements include doing away with the Simple IK constraint (although it’s still backwards compatible with older files) and using a Chain IK constraint system.

For keyframes, a new default interpolation mode- Bezier-Clamp- helps control movement by not overshooting or undershooting. Tangents of Bezier-Clamp keyframes flatten automatically when neighboring keyframes have the same value. This simple change saves hours of tweaking and, again, facilitates faster production.

Multiple characters can now be loaded simultaneously, making it possible to animate characters interacting with each other, as in a fight scene or intense dialog. Also, new enhancements to control rigs, such as double-solving, let parts of a character drive parts of another character. Picture two characters locked in combat, where both sets of feet need to be locked to the ground but their upper bodies and arms are grappling with each other.

MotionBuilder 7.5 substantially improves the undo system by building in undo/redo functionality for operations, selections and manipulations. Not all actions are supported, but the new undo system is also open to third-party developers via the Open Reality SDK, making it possible to undo actions within a third-party plug-in.

Having worked mostly with Maya, there were a few things I didn’t like in MotionBuilder, mostly having to do with the interface and keyboard shortcuts. Since this is from the same publisher, and wears a similar interface, I expected something that looks and feels more like Maya. Out of the box, though, it’s a very different keyboard set. It’s nothing that can’t be changed or learned, but for a product that’s supposed to save time, why not make it as familiar as possible for artists? The interface should be skinnable, and MotionBuilder should ship with two skins that match Autodesk’s own products- 3ds Max and Maya.

In spite of that, MotionBuilder’s streamlined approach can be a real timesaver for studios that need to churn out minutes of animation using numerous characters.