MotionBuilder 2009 Review: Greater Realtime Capabilities

Autodesk's latest version of MotionBuilder provides a realtime simulation toolset and enhanced interactivity, among other things encountered by George Maestri.


MotionBuilder 2009, the most recent release of this software, adds a number of new features like greater speed, rigid body dynamics and new shader support.  

Autodesk MotionBuilder's claim to fame is character animation. The software is a realtime character animation system that allows artists to create animation quickly and fluidly. And MotionBuilder's tools allow you to build characters using highly intelligent skeletons and kinematics, animate those characters using any combination of keyframe or motion capture tools and either render those characters in realtime or export them to other software to integrate them into larger production pipelines. Anyone using motion capture would most likely be very familiar with MotionBuilder, but the program is also an excellent keyframe animation tool as well.

MotionBuilder 2009, the most recent release of this software, adds a number of new features. The software now has a 64-bit version for greater speed, rigid body dynamics and new shader support. MotionBuilder 2009 is available for Windows XP and Vista-based operating systems.

The interface is fairly clean and consists of a number of floating palettes and viewports. Some palettes offer tools to set up and configure characters, others offer animation tools and motion editors. Characters and animation appear in realtime viewports. For those who are familiar with Maya or Max, MotionBuilder provides navigation and shortcuts the same as those packages. Another nice addition is Maya's Viewcube, which allows for fast navigation of viewports. Clicking on the side of the cube instantly changes the user's angle of view. Several different types of window layouts are provided, depending on the task -- these include ones for setting up characters, editing and storyboarding. I found the interface to be a bit cluttered and this makes the software seem a bit confusing to the new user. Autodesk provides some good tutorials, though, to help with the learning curve. Once you get the hang of it, the workflow is actually very efficient.

Characters for MotionBuilder are typically modeled and skinned in a 3D package, typically Maya or 3ds Max, but any software supporting the FBX format will work. These are then imported into MotionBuilder, where the character's skeletons are mapped to MotionBuilders own custom skeletons. These skeletons have a feature called full body IK, which allows the character to be posed naturally. Pulling on a character's hand, for example, can pull the arm, but when the arm is pulled straight, the shoulders, spine and the rest of the skeleton are affected. To lock down the pose of a character, joints can be pinned, so you can limit the full body IK to the shoulders or hips, for example. Full body IK skeletons are also available to Maya users, making integration between those two packages almost seamless. I found posing and manipulating characters in MotionBuilder to be very easy and about as close to posing a real world puppet as you can get in a 3D package.

Once the character is set up, motion can be created or added. For motion capture, you can import raw data and apply them to the skeleton. Sophisticated motion filtering tools can boil down complex motion capture data into easier to digest components. MotionBuilder can then mix together and blend motion from multiple sources, including keyframe animation. All of this motion blending happens in realtime with a high degree of interactivity. MotionBuilder's editing tools in this regard are unparalleled, and anyone working with motion capture will find the software to be indispensable.

Keyframe animation can be done a joint at a time, but MotionBuilder also has a very powerful pose editor to speed the process along. Animators can create libraries of poses for their characters and then add them to the timeline to create pose to pose animation. These poses can also be layered and mixed with other poses and animation for even more possibilities. I find pose to pose editing to be a very efficient way to animate, particularly in larger productions where animation and poses need to be reused over and over again.

MotionBuilder's rag doll solver allows characters to become digital stunt doubles, falling and tumbling with a high degree of realism. Courtesy of Autodesk.

Another way of creating motion is in realtime. Using its Live Device support feature, MotionBuilder connects to a wide variety of input devices, including MIDI controllers, joysticks, sound devices, tablets and more. These can be used either to create motion or to trigger existing motion clips. Animation triggering using external devices can be a very quick way to "puppeteer" digital characters in realtime. This is a very unique feature and ripe for creative possibilities.

New to MotionBuilder 2009 are some nice dynamics tools. Rigid body simulation allows for realtime collisions between objects. This can be very useful for visual effects, but also to those who need their characters to interact with the real world. In a similar vein, MotionBuilder's rag doll solver allows characters to become digital stunt doubles, falling and tumbling with a high degree of realism.

One thing about the software is that it's completely realtime. There's no renderer to speak of, all the rendering happens on the graphics card. This means a fast high quality graphics card is a must. I used an NVIDIA Quadro 3700 on a quad core system and it worked great. MotionBuilder can do a number of really nice rendering tricks, including normal mapping, used for highly realistic displacement maps. These can make a simple mesh look very complex. For those doing game authoring, MotionBuilder supports CgFX hardware shaders, so what's seen in the viewport will be very close to what shows up in the game.

Once the animation is complete, the characters and motion can be exported using the FBX format to a 3D package for final rendering and output. While the FBX format is very robust and can support most tasks, it might be nice for MotionBuilder to create even tighter integration with other Autodesk products by supporting direct output to Maya and Max formats.

For those who work with motion on a day to day basis, MotionBuilder is a terrific package and can save a production a lot of time. It is, however, strictly a motion editor. The one thing I've noticed is that a lot of MotionBuilder's core features are showing up in other Autodesk products.

Maya, for example, now has an Animation Layers feature similar to MotionBuilder's, and it also has Full Body IK. With such advanced features showing up in other packages, the need for separate motion editing software becomes less essential. MotionBuilder is really aimed at those places that create a lot of motion, such as motion capture studios, game development houses and film studios.

George Maestri is an animation director and producer. He is currently the president of Rubber Bug, a Los Angeles-based animation studio. He also teaches animation at Otis College of Art and