There's two different ways to assign materials with the plug-in:
- You can assign unreals material (Material asset in UE4) via the way Aladin describe to you.
Add an “unreal_material” string attribute to the faces/primitives, and set its value to the reference to the material in UE4 (right click on the material uasset, copy reference).
This material won't show up in Houdini, but will be assigned upon cook in Unreal by the plug-in.
- You can use a houdini material, and have the plug-in create an Unreal Material from it.
This time, don't use the unreal_material attribute (this one is for assign material that exist in UE4, not in Houdini)
Use the material sop, with its material parameter set to the path to the principled shader in a material network in your asset.
The plugin will then create an unreal material corresponding to that principled shader when cooking the asset.
The shader wont be fully reproduced though, only some part of it (diffuse, normal, specular, roughness…)
Don't mix both for the same faces/groups, either use unreal_material or a material node.
Here's a simple example of creating Houdini Material via the plugin:
the matnet contains two principled shader, each used by the material nodes.
The two shaders are very simple, one has a diffuse texture + metallic value, the other a simple diffuse color + emissive color.
and the result in UE4: