pumeco,

just a stab in the dark:

tiny.x in the dx7 SDK  was an animated directx .x file so it is possable to make one, but I haven't found a utility.that will do it (at least nothing I could afford)  I always assumed that 3dmax or a plugin for it had that capability but frankly I dont know that for sure.

when they talk about frames I can only assume that they are talking about geometry frames where each vertex in an object is calculated such that there is some movement of that object from the last frame. I imagine it is roughly equivalent to the frames on an avi only calculating the relative positions of the vertexes of your object rather than pixels. That's my best guess for now. 

I would be overjoyed to play with software that can make animated .x files. A link to the software would be more than appreciated if it isn't obvious from the link to the video you posted earlier.

electroglyph,

thanks for the link to the open dynamics Engine.

-TJ