Many of the 3D models available through free sites, paid websites, and even 3D modeling services and contractors are provided in .obj format with an accompanying .mtl format for the materials file. While UE4 correctly (more or less) handles .obj format models, it cannot load .mtl files. When importing the .obj file, UE4 spews random material files into the Content Browser and I have to manually rebuild the materials by importing the textures and inspecting which material was randomly paired with which UVs. This is a painstaking and annoying process which should be trivialized by the Unreal toolchain. What am I missing here? Is there an Unreal obj/mtl → Unreal format tool that I don’t know about?
This is because UE4 handles textures and materials differently from other programs,so it cannot import .mtl files that handle .obj textures. If you want to bring your texture into UE4, you’ll have to export the texture separately as an image file.