Cannot Override Textures of Imported Object


I keep running into an issue where I am unable to override the textures/material of an imported object.

The current example I am working with is a photogrammetry model (obj).
The foreground object is unedited, the background object has had a custom material created and applied to it, seen in rendered mode. The issue persists in all display modes.

Neither object is a block instance, so exploding it doesn’t help to fix this.

The only visible change is that the object with the new material applied has distorted, bad textures. I have tried creating multiple materials in Rhino, applying them directly to the model and/or via the layers panel.

Would greatly appreciate any suggestions or advice

I realise what I am seeing is potentially vertex colours? Is there a way to make the custom material override this? I don’t know how to get it off my object

Actually I think rebuildmesh is the best solution…