3ds doesn't support skeletal animation, so you can't use this format at all. If Anim8or doesn't export to b3d, then .x might work, but it will need to be converted to b3d before being loaded in Blitz. B3d is the only format Blitz can get skeletal animation from. Latter versions of the .x format support it, but Blitz can't read them. And 3ds doesn't have any support for skeletal animation at all.