Vray RT 32bit environment maps

[LudvikKoutny]

Hi,

are developers aware that Vray RT CPU does not support 32bit HDR environment maps? They are automatically clamped to 16 bit. I am now running down random scenes to determine why i always get different output out of Vray RT compared to Vray renderer, because i would like to start to use RT, but i never get similar output from Vray RT and regular Vray. I am aware of known limitations, written down at spot3d.com, but i was not able to find anything about 32bit environment maps not being supported there.

I am running Max 2014 SP2 with Vray 2.40.04

[kosso_olli]

Same here. The output from RT and RT GPU is completely different from the production Vray, especially with HDR. Also, some weirdness is happening when using falloff on materials.

[vlado]

are developers aware that Vray RT CPU does not support 32bit HDR environment maps?

Nope; works fine here. Do you have a scene where it doesn't?

Best regards,
Vlado

[vlado]

Same here. The output from RT and RT GPU is completely different from the production Vray, especially with HDR. Also, some weirdness is happening when using falloff on materials.

It would be useful to get us some examples. All our tests here behave identically so obviously there is something that we've missed.

Best regards,
Vlado

[LudvikKoutny]

I do not use VrayHDRI... just regular Max bitmap... sometimes i also feed the bitmap through color correction node into environment slot. The scene i currently work on is under NDA, but i will try to reproduce it on some simple scene.

[vlado]

Could it be because of the color correction node? We found some differences in the RT implementation when the color values are above white.

Best regards,
Vlado

[kosso_olli]

It would be useful to get us some examples.

Sure thing, I will prepare some scenes. With HDR they might get quite big though. I remember there was some kind of ftp to load the files onto. How can I get access?

Regards

Oliver

[vlado]

Sure thing, I will prepare some scenes. With HDR they might get quite big though. I remember there was some kind of ftp to load the files onto. How can I get access?

Email us to vray@chaosgroup.com and our support guys will get you the ftp info.

Best regards,
Vlado

[kosso_olli]

Vlado,
below you can find a simple scene file. As I found out, the differences between RT/RT GPU and production render are not from the environment maps, but from the falloff maps in our materials. It seems that the falloff map is screwed up when used in RT.

In the scene file there a three metallic materials, each using a falloff map somewhere. In RT these materials look way off when compared to the production render.

rt_falloff_prob.zip

[tashko.zashev]

Hello,

The problem seems to be the type of the Falloff map, shadow/light is not supported by V-Ray yet.
All other modes should produce correct render result.

[kosso_olli]

The problem seems to be the type of the Falloff map, shadow/light is not supported by V-Ray yet.

Not supported by Vray at all, or not supported by Vray RT/GPU?

Also, the other falloff modes produce different results, too. In the scene you can find a material called "FALLOFF_PERP". Assign it to the teapot and render it both in RT and Vray. The difference is clearly visible at the edges of the teapot. In RT the edge is much darker. This happens both in Fresnel and Perpendicular/Parallel mode.

[matanov]

The problem was investigated and reported early this morning but I forgot to write about it There are some limitations with GPU+mix curves and some of the falloff types but I hope soon the problems will be resolved.

[tashko.zashev]

Not supported by Vray at all, or not supported by Vray RT/GPU?

Yes for V-Ray Production, this is the only Falloff mode that is not supported yet.

Peter has replied below about the RT engine. I missed the latest material in the scene.

Thanks for reporting this.

[kosso_olli]

Yes for V-Ray Production, this is the only Falloff mode that is not supported yet.

oO

I have been using this falloff mode in my carpaint shader with nearly every render I do. Could you please explain what currently doesn't work with blend mode set to shadow/light? I never experienced any issues with it.

[vlado]

Could you please explain what currently doesn't work with blend mode set to shadow/light? I never experienced any issues with it.

First, it is not physically accurate; second, I have no idea what it is supposed to do with GI - it produces some kind of result, but I don't think it has any logic to it. Third, it is not supported in V-Ray RT at all.

Best regards,
Vlado