Normal Maps Do Not Show Correctly

[Donfarese]

We have been trying out Vray Next vs Corona and Vray has issues with normal maps. We bring in the normal maps with gamma 1 and flip green, but it doesn’t show correctly with Vray CPU, but it Does with Vray GPU.

[hermit.crab]

We are aware of the differences, however, our goal isn’t a 1:1 render result as the CPU.

Quoting Blago:
“These are different engines - not meant to be pixel to pixel the same. They use different algorithms and approaches to thing like light sampling, bump mapping, etc. If you want to use V-Ray GPU, start with it from the start and there will be no surprises.”

[kosso_olli]

@hermit.crab

We are aware of the differences, however, our goal isn’t a 1:1 render result as the CPU.

Quoting Blago:
“These are different engines - not meant to be pixel to pixel the same. They use different algorithms and approaches to thing like light sampling, bump mapping, etc. If you want to use V-Ray GPU, start with it from the start and there will be no surprises.”

I understand that there will never be a total parity between the two renderers.
However, the result shown by the CPU version is plainly wrong. It’s totally missing the lighting direction from the left. Also, the version of CPU is much less detailed. It is not a good result at all. It would be best if you guys could check the scene, there is something seriously off.

[hermit.crab]

By all means, send the scene to support@chaosgroup.com so we can take a closer look.

[M.Max]

I would love to take a look at this file too.I have few ideas that I would like to check.

[Donfarese]

Okay I’ll pack the scene, but honestly you can do it with any normal maps

[Donfarese]

Here is the scene.

https://drive.google.com/file/d/15vdOrfUGX1XbT3gRC0oEllHV3JcKatsn/view?usp=sharing

[Donfarese]

Every object in my scene renders different and wrong in ADV vs correct in RT because of the Normal maps. I’ll have to try bump mapping also and see if that’s an issue too.

[Donfarese]

@M.Max

I couldn’t download the file because of the slow internet that I have here, so I did quick test with another map and found that using Max Normal Map (show incompatible maps to see it ) instead of using VrayNomral map give almost identical result to Vray Next GPU result.so there is definitely something wrong with Vray normal map ..I don’t usually use normal maps but I remember facing a problem years back with VrayNormal map and switching to Max Normal map solved it(there were and topic here in the forum about it ) ,so I’m not sure if it is new bug or VrayNormal map has always been like this .

You are absolutely correct that Max Normal Map renders normals correct like RT in Vray ADV. But Vray using IPR doesn’t render Max Normal Map Correctly.

[Vizioen]

When I was testing the tips from Vlado I was struggling to get the right look and it wasn’t the way he described it to be.

https://forums.chaosgroup.com/forum/…s-gamma-or-not

[DanSHP]

@M.Max

I couldn’t download the file because of the slow internet that I have here, so I did quick test with another map and found that using Max Normal Map (show incompatible maps to see it ) instead of using VrayNomral map give almost identical result to Vray Next GPU result.so there is definitely something wrong with Vray normal map ..I don’t usually use normal maps but I remember facing a problem years back with VrayNormal map and switching to Max Normal map solved it(there were and topic here in the forum about it ) ,so I’m not sure if it is new bug or VrayNormal map has always been like this .

I’ve noticed this too on tiled materials such as brick. There is no definition to the vertical grout lines.

A quick test of my own in CPU.

Max Normal. Bump 100. Multiplier 4.0. Flip green

Clear definition between the brick and grout IMO. Good micro shadows.

Vray Normal. Bump 100. Multiplier 4.0. Flip green

You read the horizontals more than you do the verticals, especially evident on the side that is in shadow. Less micro shadows too.

[Ka_Hassa]

@DanSHP

I’ve noticed this too on tiled materials such as brick. There is no definition to the vertical grout lines.

This generally happens when you don’t have a UVW Map modifier applied to your object. Is this the case in your test ?

See my example :

Now I don’t know if this is a bug or an expected behaviour.

[DanSHP]

In this example no I didn’t! Applying one resolved the issue. Many thanks!

[Ka_Hassa]

@Donfarese

Here is the scene.

https://drive.google.com/file/d/15vd…ew?usp=sharing

I can’t help with the GPU/CPU discrepancy. But to get a correct render with CPU try the suggestion I made to DanSHP : apply a UVW Map modifier to the box.

[kosso_olli]

@Ka_Hassa

This generally happens when you don’t have a UVW Map modifier applied to your object. Is this the case in your test ?.

This is the strangest solution to this problem. I have no idea why it is like that, but it needs to be fixed!

[M.Max]

@Ka_Hassa

This generally happens when you don’t have a UVW Map modifier applied to your object. Is this the case in your test ?

Now I don’t know if this is a bug or an expected behaviour.

LOL this is very strange and un expected behavior ! thanks for sharing and yes I’m sure this is a bug that’s need to be fixed !

[Donfarese]

How could they not have noticed this issue, maybe they did and it will be fixed in the 4.2 version that’s coming out. Should be news on that since this is the first day of Total Chaos.

[DaveKW]

I downloaded that test scene and it seems you can also collapse the Box to an Editable Poly or apply a Turbosmooth set to 0 iterations to fix the issue too.

[hermit.crab]

Thank you for the provided scene. It seems there are differences when rendering an object with and without using a UVW modifier. I have forwarded the issue to our developers for further investigation.