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Exporting Complex FBX with Collisions in Maya for Unreal

I am trying to create complex objects in Maya for Unreal. These objects need to have child meshes that I can manipulate in Unreal. They also need to have custom collisions created in Maya. I have found instructions for the collision naming and regarding how to create the convex collisions. We are exporting the FBX per all instructions we have found but still have no luck in Unreal with seeing the child meshes or the collisions.

Is there a requirement for which version of Maya we use?
Is there a trick to how you export the FBX from Maya for the child meshes and collisions?

These are questions that I have not found answers to anywhere. Please help.

Export the parent mesh and child meshes individually, then re-combine them in a blueprint.
Just add multiple static mesh or skeletal meshes in the blueprint and place the parent and each child. They will act as one. Just make sure you have the pivots at 0,0,0 when you export them.

hope that helps.

Thank you for your reply. When you are creating hundreds of assets, this seems like a whole lot of extra work. Isn’t there an easier way? I’ve been using Unity for years and now trying to get into Unreal since everyone is telling me how much better they think it is. This seems like an element of Unreal that is not better. Am I missing something?

Make sure you are following the naming structure shown on the page: https://docs.unrealengine.com/latest/INT/Engine/Content/FBX/StaticMeshes/#collision

As an example, for complex collision, if your mesh was named “Table”, you would name your table mesh “Table” and your collision mesh “UCX_Table”. Then, with both selected, you would export them as a FBX.

When you import, you should have the collision as of the mesh made in Maya.

UE4 can also generate collision for you but it is not custom. It is however, quite good.

Thank you. I found that I had to make sure the box for “Auto Generate Collision” is checked, otherwise it won’t find my UCX_ collision. So, we have that part working now. But, I still need to find a better way to bring in objects with child meshes. Is there an easier way than doing multiple exports from Maya?
I’m using Unreal 4.14.3.

Because Unity handles FBX files as a group of GameObjects, that you can then in turn make into a Prefab, the “mass export” of a bunch of meshes is a bit easier.

Unreal handles assets differently and I do not know if there is a way to do something similar. It may be needed to individually export every mesh you want from Maya and then you can mass import them with UE4.

Kyle, not to divert this thread, but regarding FBX export and meshes, is there any difference inside UE in regards to hidden performance hits or anything to watch out for, when importing ex:

1 - FBX file (from Max in my case) that is generated from multiple unattached body parts inside max, each body part has its own skin modifier. And then they are all selected together and exported as a single FBX file into Unreal.

VS

2 - FBX file that has all these different parts attached together as a single mesh inside max with a single over all skin modifier driving everything.

(2nd point would be a nightmare to skin which is why it is not a common practice).

Please note that I understand that UE will treat both of them as a single imported mesh, and also this question is not about the Multi material setup as that would always be true and the same regardless of the options above, it’s just to know for sure if UE is treating the two options any differently in regards to possible performance or anything unforeseen like that.

Thank you.

I don’t believe there would be any performance issues that are any worse. I mean, you always have to factor in the number of polygons you are drawing, with how many materials; as in, if you draw a bunch of individual meshes with individual materials, I imagine its more expensive than have a single mesh (or smaller number) with a single material.

I am honestly not the best suited to ask this and am simply answering from the little experience I have managing 3D assets and materials. I will try and find a person with more experience to respond.

Thanks Kyle, that would be great to know. I guess it’s most likely what you said but the question’s been at the back of my mind for a while now.

Hey William K,

So in this instance Kyle is correct in that, using less overall meshes and unique materials is going to reduce draw calls, so making sure in your 3d application (Maya or Max) you have condensed it down to a manageable and sensible amount of meshes will really help with performance in the long run. Obviously, you want to make sure you are still getting your point across and not sacrificing the overall idea.

Cheers,

Andrew Hurley