Trouble's with Normal Map

anonymous_user_5728569b · February 17, 2016, 11:52pm

Im trying to improve my Character texturing.
However in UE4 im getting problem’s where the seam is showing up really strongly.
I know it’s not the material or the mesh as it look perfectly fine in blender.

Side by side of the Mesh in Unreal… Left Without Normal Map, Right With Normal map

How it look’s in Blender

I want to get my bake layers looking right before moving forward to finishing off the rest of the texturing.

anonymous_user_94ee93a4 · February 18, 2016, 1:00am

Welcome to the world of light chunks defined by UV seams. This is just what it looks like in your picture - it’s really the first thing every artist encounters in the engine.

In short, your UV map seams define the way a model is lit with a normal map. If you split the UVs of a model in different pieces, the polygons having these UV chunks will be illuminated differently in the normal map. It’s almost the same result as splitting the model in different smoothing groups. This, also, though not related, presents problems with cylindrical objects; in the upper horn of your creature, in the seam, the light is ‘coming’ from two opposite directions - one from the right and from the top.

Bottom line, you can’t overcome this. The solution is either unwrapping your model as less chunky as possible, having the seams where the player can’t see them (the inside of the arm, for example), or hiding the seams with additional geometry on top.

ZacD · February 18, 2016, 2:42am

The seams shouldn’t be that bad, either the normal map is inverted (try inverting the green channel), or the normal map isn’t imported correctly (make sure it looks blue in the material editor).

With a correct and sync’d normal map workflow, you shouldn’t get seams.

anonymous_user_66a1d5a5 · February 18, 2016, 6:24am

;476237:

Welcome to the world of light chunks defined by UV seams. This is just what it looks like in your picture - it’s really the first thing every artist encounters in the engine.

In short, your UV map seams define the way a model is lit with a normal map. If you split the UVs of a model in different pieces, the polygons having these UV chunks will be illuminated differently in the normal map. It’s almost the same result as splitting the model in different smoothing groups. This, also, though not related, presents problems with cylindrical objects; in the upper horn of your creature, in the seam, the light is ‘coming’ from two opposite directions - one from the right and from the top.

Bottom line, you can’t overcome this. The solution is either unwrapping your model as less chunky as possible, having the seams where the player can’t see them (the inside of the arm, for example), or hiding the seams with additional geometry on top.

I have no idea what this is on about, but it is totally wrong.

UV seams do not cause lighting breaks on mesh with a correct normal map, otherwise they would cause lighting breaks on a mesh with no normal map.

anonymous_user_94ee93a4 · February 18, 2016, 6:54pm

I’m talking about this.

It’s a 2x2x2 box with all of its polygons divided in single UV islands, with a standard opaque material, in detail lighting mode. The normal map is 16x16 pixels, completely flat.

Now, when you do correct UV mapping…

ZacD · February 18, 2016, 7:05pm

Can you post the files you are using , Google Drive or Dropbox?

anonymous_user_94ee93a4 · February 18, 2016, 7:11pm

It’s just a box, really. What I mean is that the UV is a space and has two directions, so everything inside it has to follow the same rule. If you rotate a UV island 180 degrees you will get the seam, which you can’t see unless you plug something in the normal slot of your material.

anonymous_user_5728569b · February 18, 2016, 7:40pm

I fixed the problem… it’s not down to there just being a seam, it was just the difference between the Texture density between the 2 area’s causing the problem