Tangent Seam

Hi everyone,

I've had an issue with normal map seams as detailed in this thread,

http://forum.unity3d.com/threads/3ds-max-normals.281450/

At first I assumed it was the workflow between 3ds max and Unity but the more I've investigated the more it seems this is a technical issue with Unity.

This thread from polycount last year also highlights the issue,

http://www.polycount.com/forum/showpost.php?p=1931099&postcount=253

I'm planning on cross platform deployment for the project I'm currently working on, so changing to deferred rendering does not solve the problem. The application I hope to create will have models at extremely close inspection and so therefore I cannot hide UV seams although I don't think I should have to.

Can anyone advise or move my previous thread from the external category to a more appropriate location please?

Cheers,

 

Hi everyone,

To summerise where I am at the moment with this;

- Unity set to forward rendering
- Sphere model has been UV mapped into two halfs
- When a blank diffuse shader is applied in Unity the sphere looks fine
- When a blank bumped diffuse or bumped specular shader is applied a seam appears

No maps are plugged into the shaders so it's not down to workflow.

Deferred rendering will get rid of this seam but this is not an option for me on the project I'm working on.

Any advice please?

Cheers,

 

Before baking the highpoly down to a normal map try this:
1) Where there is a UV Split, create a hard edge in the lowpoly (with your sphere this should probably result in two smoothing groups)
2) Triangulate your lowpoly
3) bake - make sure to add a reasonable padding (see the Render To Texture menu) to your baked uv shells
4) export the triangulated lowpoly mesh to Unity and see if this resolves the error

Ususally you should not need to have a hard edge wherever you have a UV split. But maybe it works. One of the most important steps however is the padding - otherwise your mipmaps will eat the normal information away.

 

Hi Marco,

Thanks for your reply but this does not work for me.

I keep finding rough bits of information relating to the issue but can't find a solution that works.

http://forum.unity3d.com/threads/seams-apparent-in-unity-when-i-put-on-my-mesh-s.96239/

This is a thread that illustrates the issue has been going on for some time.

 

True, this topic appears once in a while. The thread over at polycount that helped me most was this one:
http://www.polycount.com/forum/showthread.php?t=107196

I just gave it a try and created a highpoly and a lowpoly target sphere in Maya. The target sphere is split in half within the UV layout. No hard edge at the equator. The normal map works well - no visible seam. Unity Beta 5.
Not sure what might be wrong with your setup - might be 3dsmax that spits out a strange normal map.

 

Currently on unity 4.5, ive tried the export from maya also with the seam showing. Could you let me know if you've got deferred rendering on and also what shader you're using please?

If it's not inconvenient could you send me the sphere to try in the scene?

cheers

 

There's been an update over at the polycount thread;

http://www.polycount.com/forum/showpost.php?p=2194852&postcount=21

I've attempted a custom shader with shader forge but I'm no shader wizard, can anyone else confirm if it is a shader issue?

Cheers,

 

Hi everyone,

After a fair old search I can confirm it is indeed a shader issue.

A programmer colleague of mine has created a new shader for me and voila, no seams!