I have a few xfrog plants from 3d mag cds that are just in native xfrog format and wish to convert to format vue can use using xfrog 3.5 , any one know the pros and cons of any of the file formats that they can be converted to when being used in vue?

wavefront .obj ,Autocad .dxf ,lightwave 6.5 lwo ,3dstudio .3ds all of which vue can use , but do they produce any differences ? render times ? poly count?

thanks for any help any one can offer