Why am I seeing a UV issue with my model?


I don’t know if that question belongs to UE4 field so here is my question. I’m working with scanned models in Blender like that: Laurana 50k by jmil - Thingiverse

I followed the steps to export the model to fbx and imported it to UE4. Until here everything it’s okay as you can see at the next screenshot the model and its UV map imported correctly:

The problem starts when I apply a material. I don’t know how to avoid that:

I don’t know if it’s a Blender issue or if I can override this with some material feature that allows to blend the division between two UV map zones. Is there any workaround?


It might be related to the lightmap. I noticed you have just one UV channel, that means the editor will use that UV map for lighting as well and in that UV map I’m not sure if the problematic areas are connected.
Or it could be the texture from the material, maybe that’s exactly how the texture looks in that area, or the normal map. Check those too. :slight_smile:

You’ll have to remake the UV’s of the model in Blender. The current UV layout is pretty messy but the model doesnt look like anything too complicated so follow some head unwrapping tutorials like this one if you dont know how to do it: Blender 3D Tutorial - UV Mapping How to Unwrap Character Head by VscorpianC - YouTube

Thanks! I added a second UV channel (with a lightmap unwrap from Blender) and still persists the problem. I’ll follow the @Jacky suggestion of avoiding the actual UV mess and create a better unwrap as I see at the tutorial. The challenge is how I deal with the geometry… bloody messy if I compare with the example of the tutorial!

PS: I followed a few tutorials of how to import Blender meshes to UE4 and still don’t understand why you need two UV channels and if they must be the same. Any good tutorial?

After marking a few seams on the model in Blender before the unwrap I achieve a better result! Thanks!

Left: using smart unwrap option
Right: marking seams and using unwrapping

The reason for 2 uv channels has more to do with optimization than anything. For the lightmap, the actual texture is created by the computer, so it doesn’t need to be optimized for ease of hand painting. IE: there can be a ton of islands and non-contiguous areas all over the place.

Now, for the unwrap that you want to use for apply the texture, obviously one key for it to work well is to minimize the amount of seaming there is because as we’ve seen in your example, each seam is a potential trouble spot in terms of texture mismatches.