Hi,
my problem is when I make models with mirror UV the normal map start to show seams.
what is the solution ? did this problem fixed in the new version ?
I am using softimage 2015,
I try a lot to fix the seam but doesn’t work what I miss ?
Hi Klo Works,
Can you attach an image of the problem you are having? Also, is this after you’ve brought the mesh and made the material in UE4?
As with Normal Maps and texturing there are some thing to consider: on your first UV channel you can have tiling textures and UVs with no issue, but for your second UV channel you’ll want to have a separate UV with no overlapping polys to make sure light bakes properly.
Thanks!
Tim
Seams on mirrored meshes can appear from incorrect tangent/binormals. What setting did you use to import your mesh in UE4 ? Try maybe to import your FBX file only with “explicit normals” enabled and with “import tangent/binormals” disabled.
Be sure to set your FBX file format to the correct version, if you are using Softimage 2015, export your FBX as a 2013 file version (it’s available in the export setting normally).
You can’t mirror normal maps. The reason they work is because the red and green channels are actually shadow information. If you mirror the normal map that information is also mirrored. So you have shadows on the wrong side according the the light source. You can solve this issue with some complex material networks or just tile your texture which is much easier.
the problem I use mirror overlapping to get more space in UV for my modules, and for my light map I use separate UV.
my problems with the normal map when I use mirror or symmetry UV I start to see seams . you can check my files.
Ok here images show how I do :
in softimage :
export :
Unreal setting :
the problems :
the Files :
I will REALLY happy if you see the files and knows what the problem in it.
I really try a lot and I hope find the solution here.
thanks
the problem I use mirror overlapping to get more space in UV for my modules, and for my light map I use separate UV. my problems with the normal map when I use mirror or symmetry UV I start to see seams . you can check my files.
Ok here images show how I do :
in softimage : http://i.imgur.com/HZpEAli.png
export : http://i.imgur.com/ZMM2OM4.png
Unreal setting : http://i.imgur.com/c4a3mUX.png
the problems :
the Files :
I will REALLY happy if you see the files and knows what the problem in it. I really try a lot and I hope find the solution here.
the problem I use mirror overlapping to get more space in UV for my modules, and for my light map I use separate UV. my problems with the normal map when I use mirror or symmetry UV I start to see seams . you can check my files.
Ok here images show how I do :
in softimage : http://i.imgur.com/HZpEAli.png
export : http://i.imgur.com/ZMM2OM4.png
Unreal setting : http://i.imgur.com/c4a3mUX.png
the problems :
the Files :
I will REALLY happy if you see the files and knows what the problem in it. I really try a lot and I hope find the solution here.
Hi Klo Works,
As others have suggested above mirroring UVs is not the best option when using normal maps. There are ways around it but it requires editing your Normal Map in an image editing program like Photoshop. You can find a tutorial on Polycount (Link Here). This may be something you may choose to do or not. The easier method by far is to use unique uv space for each uv island of your model.
Another issue with your models is that you absolutely need a second UV channel for your lightmap. Especially when mirroring or overlapping any UV space. All the lighting for static meshes gets baked into a lightmap. Currently the mesh will have a bad lightmap due to overlapping UVs. If you’re not familiar with lightmapping you can find the tutorial at the link here.
I hope this helps answer some of the issues you’re seeing!
Tim
UPDATE: 4.2 Preview Link Here
Hi Klo Works,
We recently showcased some features that are coming in our UE4 4.2 release. One thing in there that may benefit you is the update to the 2014 FBX exporter.
"NEW: UPGRADED FBX TO 2014
The FBX importer as now been upgraded to the 2014 version from Autodesk.
This allows Tangent and binormals on mirrored meshes to be imported correctly
You can still use the earlier FBX plugins found in any Maya/Max version before 2014, but you may get a warning on import when using a very old file."
Perhaps this will fix your issue with the mirrored UVs and give you the results you’ve been wanting.
Thanks!
Tim
Really, Thats GREAT NEWS 
I am happy for that thanks alot
The real answer to this is to uncheck sRGB in the texture properties. It seems to use a bootlegged world normal, otherwise. It is also best to have the Compression Settings = NormalMap (if it is not).
Mirroring UVs should always be supported by engines, as they are great for optimizing texel density and not having to do re-work. Especially useful in Environment Art pipelines.
- Note: Importing a fresh normal map to the project, and relying on UE’s auto-compression algo, automatically sets these properly.
