This is an old post - so perhaps this udpated fix is already known - but thought I’d share.
If you want to force a material order in Maya so that they import in that same order in UE4 - use this naming convention:
- Use a prefix of “M_” and a suffix of “_skin00” or “_skin01” etc.
Examples: - M_MaterialName_skin00
- M_MaterialName_skin01
- M_MaterialName_skin02