I don’t know how to go to 3ds, but my advice would be to just output some (high res) clean plates out of 3ds, and use some clever compositing and layering to blend the talent with the plate. Or buy a camera tracker, then you’ll have a slew of choices to output into. Syntheyes is VERY worth it for the money and ease of use. I think Mocha is on sale today at toolfarm.com too. 50% off is a sweet deal for software now-a-days.