Problem with irradiance map max rate in nightly vray_adv_24501_maya2014_x64_24437

[joconnell]

Heya folks,

Just having a few problems with this build, it seems that the ui isn't respecting the max rate of the irradiance map and it's defaulting to using 0 instead of whatever is chosen in the ui with either the presets or using the custom setting. In my case I've just tried using custom to get -3,-2 and it's ended up doing 4 passes at -3,0. I'm getting "Error: Exception [module=2] : Irradiance map thread // " in the script editor too.

Cheers!

John

[vlado]

I can't reproduce that in a simple scene. It is possible that you have a material (sss2, skin, or a VRayMtl with interpolated reflection/refraction) that is forcing the higher max rate. If you can send me a scene to vlado@chaosgroup.com, I will try to find out what's wrong with it.

Best regards,
Vlado

[joconnell]

Yep, there's sss2 in there indeed. I'll fire over a 2014 scene with the character swapped out but the same material.

[joconnell]

Here's a 2014 maya file with no maps, it showed the same issue in the output window for me - hope it's the same over your side.

Cheers!

vray_2.45_nightly_irmap_max_error_for_vlado.ma.zip

[tashko.zashev]

Hi John,

There is a SSS2 material (HUG:Hugo_sss_Ref) which is set to Prepass rate -1. Therefore 4 Irradiance map prepasses will be started from -4 to -1.

I'm getting "Error: Exception [module=2] : Irradiance map thread // " in the script editor too.

Unfortunately this error was not reproducible in my renders, I will try to run few more tests again.

[joconnell]

Ah - thanks for pointing that out Tashko, it was a fast sss 2 material that had a prepass rate of 0 making the change in this case.

What I was seeing was vray debug mode (that#s what I get for thinking I'm smart) saying "V-Ray debug: Rendering interpolation maps with minRate=-3 and maxRate=0" and not knowing that there was a fast SSS with prepass rate 0 in there.

Just curious on that one, I've set up a very simple test scene with irmap set to custom -3,-3 and I have a fast sss 2 with prepass rate -1. The debug mode is right (as it was before) in showing a min and max interpolation rate of -3, -1. Just wondering though, when it starts to calculate the prepasses, it does three passes which I'll assume are -3 (for my irmap at custom min -3, max -3, so only one prepass), -2 which I don't totally understand, and then -1 for my fast sss 2 which is fine. Is there any efficiency loss in this?

The last thing is whether the new "geometry based sampling" mode is stable enough to use now? The last mention I found of it on the forum was back in 2012 when it was only being tested. It seems very quick!

Thanks again for the help!

[tashko.zashev]

Hi,

Generally all Irradiance map prepasses will be calculated according to the values you have specified in the GI tab and additional passes will be added to compute the SSS2 prepass at the required resolution (rate).
So for this example setup: Irr map -3/-3 and SSS2 prepass rate 0; V-Ray will start 4 prepasses, at the first one it will calculate the GI solution with rate -3, next two passes will be very fast (V-Ray will not shoot any rays because of the Irr maps settings) and the last pass (four) will be for the SSS2 shader.

The last thing is whether the new "geometry based sampling" mode is stable enough to use now? The last mention I found of it on the forum was back in 2012 when it was only being tested. It seems very quick!

Actually I'm not aware of any issues with this SSS2 mode. There is one minor issue reported in our system, but this feature should work as expected.
There are some changes on this in our V-Ray 3 for Maya Beta builds. It is now part of the multiscattering mode list : Object-based illumination map.

[joconnell]

Hi,

Generally all Irradiance map prepasses will be calculated according to the values you have specified in the GI tab and additional passes will be added to compute the SSS2 prepass at the required resolution (rate).
So for this example setup: Irr map -3/-3 and SSS2 prepass rate 0; V-Ray will start 4 prepasses, at the first one it will calculate the GI solution with rate -3, next two passes will be very fast (V-Ray will not shoot any rays because of the Irr maps settings) and the last pass (four) will be for the SSS2 shader.

Brilliant, thanks for clarifying that.

Actually I'm not aware of any issues with this SSS2 mode. There is one minor issue reported in our system, but this feature should work as expected.
There are some changes on this in our V-Ray 3 for Maya Beta builds. It is now part of the multiscattering mode list : Object-based illumination map.

Cheers for that, it's working very nicely in 2.x!