Seam in Normal map in UDK

[easterislandnick]

http://www.nickfarley.co.uk/seam_issue.jpg

Hi, I'm making a large rainforest type tree but am having issues with dark seams in the normal map when I import it to UDK. My creation process is -

- Low poly in max where I uv map it.
- Import to Z brush where I sculpt and polypaint it. Export the polypaint to a texture using low poly model UV coords.
- Use x normal to create normal map etc.
- Import into UDK.

I get these seams in UDK and in the Xnormal previewer but not in a max viewport. I have tried exporting normals from Z brush but get the same result. These seams are in the same position as the UV seams. Am I doing some thing wrong or is there always going to be seams in the normals?

Any help in this would be much appreciated.

Thanks, Nick

[cryrid]

Try Talon's advice:
"Any seams in your UV map, those edges that make up the seams are converted into hard edges (in 3D, not your UVs) when you import it into Unreal.

So you'd have to make those edges hard on your model, then re-bake the normal map so that the normal map has been baked with hard edges expected and will therefore look correct."

http://www.game-artist.net/forums/support-tech-discussion/13103-normal-seams-unreal.html

Odd that it wouldn't look right in xnormal though, if that is what was used to bake it.

[PredatorGSR]

Did you invert the green channel? You have to make sure that normal directions match between unreal and the normal map. I think its the green channel that needs to be inverted, but try the red if that doesn't work.

[easterislandnick]

How do I make edges hard in Max? Do I give each UV chunk its own smoothing group or can I do it per edge like in Maya?

[teaandcigarettes]

I'm with Predator on this one; apart from the seam your model has some smoothing issues in UDK.

If that doesn't help makes sure that you import your normal map with the proper compression. If you didn't, you have to import it again; changing the compression method doesn't work sometimes.

[Trappe]

I dont think it´s a problem with hard edge being forced but probably with the normalmap (try flipping the green channel from the xnormal render) or possibly a smoothing error either when rendering (set xnormal lowpoly to render using averaged normals).

Dubble check your exported smoothing groups in max so they are all one.

[easterislandnick]

http://www.nickfarley.co.uk/seam_issue2.jpg

Hi, I flipped the y and it looks loads better, still a slight seam but my normals are much more noticeable which is a relief!

Not sure how to remove that last seam, might just put creepers over it!

Thanks for the help!