Meshes that have multiple Material ID's and multiple assigned materials in UDK have problems when the model is 're-imported'. I use FBX files (with multiple meshes in one file) And when I import the (updated) models again (in the same group and package in UDK, this will overwrite and effectively update the models), the assigned UDK materials, however, will disappear or get set in the wrong order. (I do not use the re-import function since this does not work for multiple objects in one FBX file, but I think the problem would be the same.

I only use the material ID's assigned in 3DSmax and the multi-subobject material to get the material slots in UDK, I do not export any materials from 3DSmax to UDK. I assign materials I have created in UDK to the models after importing them.

Every time I re-import my updated models I have to manually re-assign most of the materials (some stay in place, others are set in the wrong slot), even though the MAT-ID's in 3DSmax have not changed.

Is there a way to prevent this from happening. (Am I doing something wrong during the import process?) And is there an automatic way to assign materials to objects in stead of manually having to assign the UDK materials to eacht material slot for each imported object?