I just modeled this mesh in blender 2.8 with a miror modifier and when i import it in unreal, the light seems to separate at the junction of the model (only in ue4, it works in blender).
I tested few changes with my material and this problem appear only with this texture. (this is a sbsar file)
I hope you could help me !
can you still see the seam in unlit view?
No its ok in unlit
it works in unlit, Lighting only, Reflection but we can see the seam in detail lighting and lit mode.
id tend to suspect the lightmap uv is overlaping so static lighting won’t work. if you check ‘force no precomputed lighting’ in the world settings and rebuild you lights that will clear out any lighting info that may have been baked into the asset.
you can also apply the mirror and make a lightmap uv prior to export from blender if you want to use static lighting.
I turned off “force no precomputed lighting” and I remake my lightmap unwraping with the mirror applyed but its dont change anything… I tested to replace my material with a pretty similar starter material and the problem is fixed. Maybe its just a material problem ?
maybe, is it just the normal map creating the seam or does it show up with diffuse alone?
You where right. I disabled normal and the seam disappeared. I still don’t know why he’s doing this, but I’m going to push in that direction.
I guess you could try masking one side of the mesh and inverting the normals in the shadergraph.
to mask a side of a mesh it’s just 'local position->componentmask(r or g) ->saturate ->ceil
then use that as the alpha of lerp between the regular normal and a normal that’s been inverted with the oneminus node.
that said, not sure if a simple inversion trick is going to make the normals point the right way.
I did that, I think it might be a solution. It still doesn’t work, but I probably had something to do with it. Is this graph correct?
no more like this…
you should either the r channel or the g channel not both. depends on the orientation you imported the mesh with.
Huge thanks I will try that !
if you cant find a way to get it to work you can always apply the mirror and rebake the normals and just have a uv map for the normals and another for the diffuse.
googled around a bit an found some posts talking about the same issue.