I am feeling insane because I have done this successfully in the past- I'm just trying to get some destruction into UE4 with a different material on the interior faces, but no matter what I do, the mesh appears in Unreal with one generic material slot whose name bears no relationship to any of the material names in Houdini. Its quite possible its something to do with the import settings in unreal rather than the houdini export but I just wanted to check if anyone had run into the same thing in 18.5 or if anyone sees something i'm overlooking.

I'm attaching a very simple example of what i'm generally doing.

We're having the same problem. I don't suppose you figured out what was missing? It's collapsing all our materials into the one generic one on Unreal-side.

EDIT: Wait, we used the QuickMaterials SOP, but we have to revert it with the reset to previous form button at the top. NOW it works. Why did they change it to a broken form? Heh.