Unreal Newb Q - UV channel #1 degenerated triangles

Unreal newbie here, I’m just trying to follow along with some learning videos (the exterior arch viz one specifically) using my own model (3DSMax & Vray).

I’m getting a lot of this error when exporting to datasmith: mesh name’s UV channel #1 contains degenerated triangles, this can cause issues in Unreal. It is recommended to properly unfold and flatten exported UV data.

Can anyone help me understand what this means? If I understand correctly, Datasmith uses max’s UVW channel 1 as Unreal’s UVW channel 0, so is the channel listed above related to the 3DSMax channel 1 or the Unreal Channel 1?

Also what’s the best solution to this? The error seems to mostly be cropping up on geo imported from the architect’s Revit models, which is no surprise, as they are a mess.
Would there be any harm in combining them all in to one mesh before unwrapping (channel 2!?)

Any help appreciated, go easy on me!

Going by the error message, it is complaining about faulty or impossible geometry known as degenerated polygons (triangles in your case), so the best case would be to get rid of those degenerates. As far as i understand, it happens, if f.e. two or all three points of the triangle are at the same identical coordinates, causing the triangle having literally no area. So combining the meshes would probably not help, but maybe you have an optimizing command, which can get rid of such triangles, or merge multiple vertexes into one, that are to close together or even at the same spot. Then unwrap it.

Thanks, that makes sense, hopefully it’s just as simple as welding vertices together in 3DSMax then, but the Revit geo doesn’t always make that an easy task.

I’ll investigate some more, but that’s a helpful explanation.