When I found out that the kW Xport could export fine using the biped system and the physique modifier for skinning, I desided to learn how to use that stuff. My thinking was that I could simplify the animation work for the character in my game. What I'm finding is that the animations created in the samples and tutorials usually move the charater away from it's original local position (like for walking, running, etc) but what you want for model exported for a game is a model that walks/runs in place, right? For instance like the tiny.x model. She looks like she's walking but in the DXviewer she just walks in place, like she's on a treadmill or something. That is the desired situation for a model loaded into a game, because the engine is responsible for moving the character around in the world space. However most of the 3DS tools for animation create a character that moves around, and when exported it is not what you want for the game. Is there good techneque in 3DS to use the fancy tools like footsteps and stuff or animate a normal walking character but then somehow modify it to not translate the center of gravity as it animates?

Lock the parent bone from moving? If you're using 3DS Max - Select the parent bone. Under the "Hierarchy" tab (to the left of the "motion" tab), click on the 'Link Info' button at the very top of this tab. Under the 'Move:' section you will find 3 check boxes for the coordinates X, Y, and Z. Check all three and your parent bone will be locked in place but still rotatable/scalable. To move it again, uncheck these boxes.

There is an 'in place' button that keeps your character at the origin. It's in the biped rollout under 'modes' and looks like 2 circles. HTH

Locking the parent bone will work; however my question was more about using the techniques from tutorials and samples (which do not lock the parent bone) or even using the footstep feature of the biped system (which AFAIK requires that the biped move from one footprint to the next) and then modify it somehow so the resulting animation goes through all the motions, but doesn't actually go anywhere.

My understanding of the "In Place Mode" feature was just a tool to keep the viewport centered on the character, but that ultimately the animation was still the same, and thus the exported animation data would still contain an animation that moves the center of gravity around. I would love to find out I'm wrong about this, does it in fact change the animation, or just the viewport focus?

From the 3DS max docs:

Quote: In Place mode, doesn't actually create an "in place" animation, it is just a viewing mechanism. To actually change the animation so the biped really stays in the same space, create a dummy object and link the COM to the dummy. Then keyframe the dummy so that the biped stays in the same place as the animation progresses.
To see an example of this, open the file "in_place_dummy_final.max"

Apparently In Place Mode doesn't do what I want, however I think I've answered my own question by looking at the docs. I don't know what it means by "keyframe the dummy"; however I intend to find out!

Thanks for pointing me in the right direction Prototype!

In the intrest of sharing what I've learned, I have an update. I could not find this "in_place_dummy_final.max" file that the docs speak of, but I experimented with a dummy object and linking the COM to it. I'm finding that the only way to keep the model at the origin is to acutally animate the dummy object at same rate and distance in the opposite direction of the walking motion, thus counter-acting the movement.
This feels kind of clumbsy but it's the only thing I've had any luck with to this point. If anyone has a better way to accomplish this I'd be grateful, otherwise I'm moving on with this approach.
Thanks again for you help!

At the risk of beating this topic to death, I have another update.

Because the walking motion accelerates and decelerates it is very difficult (read: impossible for me) to move the dummy object just right to counter-act the motion. I'm convinced this is not a right approach for this task.

This makes me wonder, was the biped system and physique modifier not intended for game models? maybe I'm trying to use the wrong tool for the job here. What are the most common techneques for animating a character in 3DS max such that you get a model that doesn't move away from it's local coordinate system, it smoothly repeats when you replay it, etc... Are the biped and physique tools simply not appropriate for this use?