One thing I didn't quite understand.... if you create the runway (a walk sequence?) in MD3, can't you also render it there?

 

Do you already have files in those formats that were given to you or are they asking you to create those files in the first place?

 

You could perhaps find another program that can also load some of these frmats, if you really must work with these formats. Perhaps Cinema4D has imports capabilities for those or some of those?

 

Are they looking for a solution that dynamically lets the web visitor pick a different design and see the walk sequence re-play in realtime with the changes? That's very different from using any tool to render an animation out as a video file (avi, mp4, quicktime,...whatever format) and then loading it to the website or embedding it from youtube or similar places. You might want to clarify exactly wat they are looking for as deliverable.