Is there an option in Arnold to ignore UV winding order?

[autodeskguy]

I've got a scene in which there's a normal discontinuity issue across all UV seams on one UV island of a mesh:

There's no issue when using the hardware renderer:

This is because the left leg island has opposite UV winding. The viewport 2.0 renderer appears to ignore winding. 

I would like to know if there is a way to ignore UV winding in Arnold, and if not, can the feature be added?

Thanks!

[Christoph_Schaedl]

Are you sure its not just a flipped green or red channel? There is an option in the bump node for Arnold. 

[Anonymous]

Not only am I sure, but you can be, too, if you look at the third image.

[autodeskguy]

Not only am I sure, but you can be, too, if you look at the third image. It clearly shows what's happening as I described.

[autodeskguy]

Does anyone from Autodesk actually read these?  Am I in the right place?

[damaggio]

This is for Vray but check all Arnold rendering settings in the documentation to see if there's something similar, sorry that's all I can offer, we use Vray only.

Uninverted normal bump – A global option to prevent inversion of normal bump in tangent space on flipped UVs.

https://docs.chaosgroup.com/display/VMAYA/Textures+Overrides

Good luck.

[autodeskguy]

Yep that's exactly the sort of thing I am looking for.  Does autodesk actually monitor this channel?

[Christoph_Schaedl]

I fear the only way is to rebake with unique uvs  or use a displacement map. Arnold is traditionally a renderer used for fvx and not rendering game assets. 

I know thats no excuse. But does explain why there is no solution. 

[autodeskguy]

Any rendering which relies upon UV-normal will be affected.  This includes displacement.  As someone above pointed out, this feature is available for Vray.  This isn't specific to the application of the renderer, it's a feature which other software renderers do have.

Do you work for Autodesk?  Can you pass this onto the Arnold team?

[Christoph_Schaedl]

Im not an Autodesk employee. 

I passed this thread to the Arnold Team. 

[autodeskguy]

cheers

[Christoph_Schaedl]

There is no solution beside rebaking. 

They made a internal ticket. 

[hamsterHamster]

Just an idea, with no working proof... Can't you "invert" the displacement for that uv-shell? either edit the texture or paint some control mask for texture mix.

[Anonymous]

I appreciate the thought, but I'm actually looking for the specific feature I requested. There's background but it's not going to be fruitful to get into it here.