Normal maps appear wrong in RT GPU

[MattClark]

I can't supply any images right now, but just doing some tests with RT GPU in Vray 3 and the Normal maps aren't rendering correctly, either through the Normal Bump map, or the VRayNormalMap.
Hard to explain the error, it looks maybe as if a channel is flipped, but none of the options for that in the Normal Map rollout seem to fix it.
RT CPU renders same (correctly?) as the production renderer.

I'll try and upload some images of non NDA material, but this is confirmed on multiple scenes across different machines at the moment.

Thanks

Matt

[MattClark]

It seems that RT GPU flips the green channel of the normal map, opposite to that of RT CPU/Production renderer.
It also appears you cannot use the 'flip green channel' in the Normal Bump map, as this is ignored by GPU (and also it would then flip the production renderer too), ideally we need these to be treated the same.

[vlado]

It seems that RT GPU flips the green channel of the normal map, opposite to that of RT CPU/Production renderer.
It also appears you cannot use the 'flip green channel' in the Normal Bump map, as this is ignored by GPU (and also it would then flip the production renderer too), ideally we need these to be treated the same.

Thanks for the pointer; will make a note to fix it.

Best regards,
Vlado

[MattClark]

I seem to be having a similar problem with Vray RT CPU too, this is in the latest nightly, not sure how long it's been like this, but the green channel seems flipped to the production renderer again.

Also, toggling the Flip Green (Y) channel in the the Normal Bump seems to actually break, in that toggling on and off doesn't revert the render to how it was before.

[vlado]

Can you show me?

Best regards,
Vlado

[MattClark]

Emailed a file...