DBR - Darker Buckets on Slaves

[alexyork]

I've just fallen prey to the dreaded "darker buckets" issue... is there any fail-safe solution to this? Every single bucket on my single other slave renders darker during IRmap calculation. I know that the work-around is to render IRMaps on the local workstation and then DBR the final render but I would hope there is a workaround for the real issue at the core. Curiously everything seems to look correct during the final beauty pass... so maybe just difference with the way it's showing during IRMap calc but not a problem with the actual recorded pixel data?

Naturally all the same max and vray versions, and plugin versions, Gamma set the same on both machines, UNC paths, no missing maps etc.

I can't think of anything else to check?

It almost looks like the slave machine has SRGB mode unchecked, which it doesn't appear to in the maxstart.max or vrayspawner2013.max files. I've tried reinstalling vray, restarting the slave but no luck.

I've attached a screenshot to show what's happening. Asus = local Gigabyte = slave.

[alexyork]

Also, to follow up, this is happening across the entire image/scene, over all materials, even ones with no texture maps. So it does look like a gamma or Frame Buffer issue or anything other than maps basically.

No firewall being used either.

It could possibly be an issue with local IRmap temp location? Who knows...

[deflix]

if you are you using an hdri can ur slave see it?

[alexyork]

if you are you using an hdri can ur slave see it?

no HDRI. just a simple gradient for the env override and separate one for the background map.

and SRGB definitely enabled on slave.

[deflix]

what happens if you test render with mat override?

[alexyork]

what happens if you test render with mat override?

I will test this shortly. And I'll test with and without lights too to isolate those potential issues.

[deflix]

I will test this shortly. And I'll test with and without lights too to isolate those potential issues.

Possibly no point in rendering without lights

[alexyork]

Possibly no point in rendering without lights

Well not if it'll be black, no! But I think turning lights off might at least rule it out.

[alexyork]

Ok so using a regular vraymaterial as override same problem occurs. all lights off, same problem. srgb off when sending render out, same problem.

No luck here! I'm mystified......

The only thing looks to be Gamma. How can I double-check that this is correctly set on the slave?

[alexyork]

I'm wondering if it's something to do with permissions and maybe some kind of local temporary file the IRmap is being written to before it's saved to the desired location for access in the beauty pass.... maybe this location is conflicting or not accessible across the network.

The issue ONLY happens when using IR. Not when using Brute Force.

[deflix]

afaik the scene opens with the same settings it was saved with on your workstation. I'm happy to debug for you here if you send me the scene...

[alexyork]

afaik the scene opens with the same settings it was saved with on your workstation. I'm happy to debug for you here if you send me the scene...

Yep I think we should be able to rule out a gamma issue. I can't send this file out im afraid due to NDA. It's a really weird one. I'm almost 100% sure that the actual IRmap data in the buckets generated by the slave are identical to those produced by the local workstation, except that they display differently in the FB, because they render correctly in the render pass. I think the difference in brightness would show up in the render pass if this was not the case. So it might actually just be a FB problem and the IRmap is being generated correctly.

[deflix]

I'm almost 100% sure that the actual IRmap data in the buckets generated by the slave are identical to those produced by the local workstation, except that they display differently in the FB, because they render correctly in the render pass.

I'm not 100% clear what you mean here? Are you saying that the final beauty looks fine?

[alexyork]

I'm not 100% clear what you mean here? Are you saying that the final beauty looks fine?

That's correct. It's just the IRmap pass that appears darker. Final render identical as if rendered on local machine only.

[deflix]

That's correct. It's just the IRmap pass that appears darker. Final render identical as if rendered on local machine only.

I wouldn't worry about it then
I'm off home - have a good weekend!