Has anyone ever heard of this...BajaEngine...

It seems quite capable. Except the download is not pre-compiled.

Post here what you think of it.

The feature list looks decent (other than the XSI dependancy) but judging from the demos the Mac build is based on GLUT and doesn't properly capture the screen or mouse (mouse deltas seem all over the place too). Basically it ain't ready for prime time - certainly not the Mac build - the animation demo also crashes on startup on my machine...

You can use it with Maya...maybe some other prog like Blender (blender...can export to xsi formats and other not-so-well-known ones).

I do hope it stays free.