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?

I Have tried to use the Skin01 Skin02 Skin03 naming option for sub-object materials. That does not work, and even if it would It resets all my assigned materials in UDK with the material from 3DSMmax. Does anyone know a method where the assigned sub-object materials will remain in their correct spot (subobject number) in UDK even after re-importing the mesh?

think it is a max problem, in maya, i have exported a ton of meshes, that use multiple materials, and assgiend them in udk, and on re-import they still maintain the proper material assignment.

Never seen max do this, so not sure if it's a max thing. What version of the FBX exporter are you using and what build of UDK is it?

Originally Posted by DeadlyFreeze

Never seen max do this, so not sure if it's a max thing. What version of the FBX exporter are you using and what build of UDK is it?

I use FBX 2012 and UDK 2012-05. I Use multiple meshes within one single FBX file for efficiency reasons. The only way to re-import meshes, from a multi mesh FBX file, is to import them again on top of the meshes in UDK (Not using the re-import feature because it will re-import all meshes at once in a single mesh.) It will remember some of the assigned materials but in the wrong order and empty other material slots.

Couldn't replicate it, tried both 2011 & 2012 fbx with same UDK build. Can only guess you have something funky going on with a mesh/material. Maybe try working backwards, use 2 mat id's see if it works add another, so on and so forth until it breaks.