Tool for rotate polygon tangents?

[joiec...@gmail.com]

Hi there,

I was traying to kind of randomize my UV shells in order to avoid tiling in my real time engine.

So I need to use textures only, not place2D transforms or anything.

So I was happily rotating and moving my UVshells and everything was right.

BUT!

Rotating UV shells indeed affect normal maps!

I searched for a similar problem in Google and found this reddit thread, which explains exactly my problem. But it doesn't show a solution.

In MAYA, I can show polygon tangents and I can clearly see they are rotated, so I guess that's the problem.

So now the question is simple: Is there a tool in MAYA for modify the tangents instead of just showing them?

I tried the edit normal tool but that one doesn't affect the tangents I'm afraid.

Thanks in advance!

[hernan.s...@gmail.com]

Bifrost graph you can do that and more. 

[joiec...@gmail.com]

I don't know how to even start using it, I guess it is time to learn it, but it is really complicated for non coding minds like mine. How would you do it?

[hernan.s...@gmail.com]

If you do not want to use BF which I recommend anyway, did you try using  this

[joiec...@gmail.com]

I surely want to start using BF, but it's hard to know which nodes to use for such task or even start thinking that way.

Yes I tried the vertex normal edit tool, but it just rotates the normals, not the tangents..., or I am not using it properly :(

[joiec...@gmail.com]

The problem with tangent normal maps and UV rotations continues blowing my mind...

It affects the shading, specially specular shading, even with a completely flat tangent map.

So, if I create a one color image file (RGB 127,127,255 which is the default tangent if I'm correct) and apply it as tangent normal map to a surface, it looks exactly the same as expected.

OK.

But then, if I rotate a face, it changes the shading, and as far as I understand this thing, it shouldn't because the tangent of the normal map is not pointting to anywhere (weel, just plain Y axis), see this screengrabs:

Can anybody confirm this and how the hell fix it?

[joiec...@gmail.com]

Well, it seems that MAYA's color picker was not behaving normally because the numbers were not in linear space, or yes, I don't really know. The question is that my normal map was handmade and I forgot to render it in linear space and it was in sRGB instead, so even when I loaded it into MAYA in RAW format, it was in fact modifying the shading because of that color space. Now that I fixed that error, it works as expected.

Cheers!