A source or destination cal3d file is either a skeleton (.xsf or .csf), a mesh (.xmf
or .cmf), an animation (.xaf or .caf) or a material (.xrf or .crf). The files with an
extension starting with an
x denote XML files (.xsf, .xmf, .xaf, xrf) and the files with an extension starting with a
c denot binary files (.csf, .cmf, .caf, .crf).
source is a file of a given type, the
destination is expected to be a file of the same type.