Exporting a combinedmesh from Maya to UE4 problem

I have a glass window object in maya, which is a combination of 3 different objects (glass, frame and handle) each has its own materials. See picture:


And here is the hypergraph:

When I export it to unreal, I only see one material

So I can’t tell if the Maya FBX is not exporting all materials or Unreal cant read the materials, but for another object with two material, I see both materials there - using the same export and import settings.

Also when I build the lighting, I get this error:

> Lightmap UV are overlapping by x%.
> please adjust content - Enable Error
> coloring to visualize.

I layout out each individual object UV similar to this UV layout:

but after combining the objects the UV set looks like this:

I assume that’s why it’s giving me that error?

Any help would be greatly appreciated. Thanks.

I think i can help you with the “Lightmap UV are overlapping by x%.”. I had the same problem. As i am making a mobile game i overlapped my UVs
alot to keep texture sizes down. But then that messed up the lighmaps in maya. So i made a extra UV set in Maya, one that overlaps for texture. And one that does not for lightmapping. That got rid of the warning message and the weird looking light build.
As for the other problem, have you tried to delete history and freeze transformations on each object before combining?

Yes I have deleted history for it and freezed the transformation.
I did an experiment, I imported the fbx back into maya and noticed the materials are gone! Is there a bug in Maya’s fbx export tool?
so you created non-overlapping UV’s layout for light-maps? meaning for combined objects you created a separate UV set?

post-edit:
I exported the object using the 2017 fbx exporter version and got the following error white exporting:
LOG: [WARNING] Unable to export some material(s) - The plug-in does not support the following material types:
Material will be exported as a grey Lambert material.

It’s a Maya issue. I will post this question in a maya forum and point to the answer here.

So far i have only combined meshes that use one materials. Objects that require several materials i keep separated. I dont know if its the proper way to do it but i remember reading somewhere
in the UE4 documentation to avoid using several materials on the same mesh if you are making a mobile game.
I think its safer to export all materials to UE4 as basic lamberts or phongs and then create the new material in UE4 as UE4 ,being a game engine it dosent support all the materials in Maya, as Maya is also for film production. Games have a very different approach to how they use light and materials as they need to be real time rendered many times per second where a movie
can have a frame that takes hours or days to render.
Therefore sending over complex materials from maya will probably result in changes to settings and nodes, so even the ones that are supported might still need work after export if alot of work is done to then in Maya. So i think it saves time creting them in UE4
to begin with.

So for this example of a door, you import 3 different models and combine them into a single model in unreal? This is a pure guess, but don’t you think you will slow down the collision detection work?
Regarding the material type, I created 3 different materials in Maya all of them are basic lamberts with different color, so then I can apply the proper textures in Unreal. It’s not so much I care about the material itself, because during import I don’t import the material. However, I do all this in order to maintain the “placeholder” to apply different materials to the object. Maybe this method isn’t the proper way of doing things?

I havent combined them yet, but i have a bunch of models consiting of several meshes. As for collision detection i will make very few collision auto generated unless they are simple box collision. Also theres no jumping in my game so most collisions will be simple shapes at the base of objects.
What do you mean by place holder, uv coordinates? I dont think you need to import a material to maintain the UVs, not 100% sure as i havent imported a mesh without material yet. This got me curious tho, i will experiment with it abit later.

I also figured out the proper way of doing this but it’s a bit incomplete. For example my door has 4 objects. In Maya I group them together and I reset the location of the pivot, (usually at the corner) and export the group into fbx, And in UDK, I select combine meshed when I import the FBX and it works out how I wanted it to be -A single mesh with multiple materials. Though I don’t know how to set the collision mesh name in Maya. Is it the group name with UCX pretended?