Extending FBX Importer

Does anyone have suggestions in regards to extending the FBX importer to allow further customization to imported models and Materials? For example can we hook into a postprocess materials, postprocess models event through blueprint, or through C++?

Currently, the limitation of importing materials is that unreal only imports the diffuse map and normal map of the model. Defined here (
However, I would like to extend it so that it also imports the roughness map, and connects specific channels with specific inputs of the material. This way I could customize the whole material creation process to fit my needs.

Any ideas, suggestions?

I can understand that, but as an extremely unorganized computer user. I have to tell you I dont put many textures on my materials in modelling software.
I try to structure my ue4 project as epics standard with the folders mesh, materials, and textures. So i import the mesh into its folder, and move the materials to its folder, and then import textures etc. so as i dont make a mess. Cause if i dont do that. I really, really make my project a cluster f—

That would be an issue with the FBX format, since it doesn’t use materials that have roughness/metallic/etc it’s not like it contains that information and UE4 just isn’t using it. What is an option is to use the format incorrectly–meaning that you could export to the FBX format and place your roughness texture in some slot that will export over, and then if you modified the UE4 importer then you could tell it to take textures from that particular slot and use it in the way you intend, just knowing that that’s the way you need to set up your materials to be exported to UE4. I think you can probably export with the Specular slot and use it that way.

This is a scripting / programming request. I don’t want to work around the limitations of the software to piggy back other features to ‘trick’ the application into doing what I want. I need to script and hook into a postprocess events but I’m not sure how or where to look. That’s what I need an answer on. Is there a way to extend the FBX importer to add another checkbox that (when clicked) evaluates some sort of custom that I can create to hook up materials.