Rendering vray passes blows out GI

[narino]

Hi all,

 

Long time lurker first time poster here. I’ve been running into this problem for the last week and for the life of me can’t figure it out. Hopefully the collective whole will be able to point me to the solution.

 

The problem happens when I check the “Elements Active” box under Render Elements. With out the Render Elements turned on everything renders correctly. But if turned on, it seems that affects my global illumination and blows everything out. I’ve attached the RGB pass with Elements turned off, and one with it turned on. I’ve also included the rawglobalillumination pass as it also looks blown out, all other passes seem “normal”.

 

Has anyone else come across this issue? As you can see I’m rendering at a super low res so I don’t think it’s a memory issue, the issue is the same at high res, with or without 3GB switch.

 

I’ll include screen captures of my vray settings as well.

 

Thank you in advance,

 

Jorge

 

 

system\software specs:

 

Windows XP SP3

2.80 Ghz AMD Phenom II X4 920

2 GB of RAM

3.25GB (with 3GB switch)

 

Vray 1.50 SP4

3ds Max Design 2011 32-bit

 

[ATTACH=CONFIG]40681[/ATTACH][ATTACH=CONFIG]40679[/ATTACH][ATTACH=CONFIG]40680[/ATTACH][ATTACH=CONFIG]40678[/ATTACH]

Edited January 5, 2011 by narino

[narino]

Hopefully has run across my issue. Either way I'll post what I find for sake of archiving and perhaps helping someone else in the future.

 

So I decided to render the original attached images at a higher resolution, per request of a friend that frequents the forum. In doing so I found out that the "blow out" is tripped by the number of Light Cache subdivisions. If i keep the number under 400 Subdivs, it renders with all the passes fine. But rendered with 401 Subdivs and up it blows out. Again this only happens if I have the Render Elements Activated. With no Render elements activated I can put in 1000 Subdvis in Light Cache and it renders fine.

 

Does this give anyone any ideas?

[John Dollus]

I have tried to replicate here but no luck.

[BrianKitts]

Are you purposely using 50 primary bounces for your IRR? What exactly are you trying to achieve with that.

 

Put it back to 1, then try your render with 400+ LC subs.

[narino]

John - thanks for the try. Perhaps it's a bug with my software/hardware? Either way I think I found a band-aid solution.

 

As increase my Light Cache Subdivs, I also have to make my sample size smaller to .01 or .005. I have no idea why the lighting blows out with Render Elements activated. But it seems this work around allows me to render out my passes correctly.

[narino]

Brian - I was trying to push the exterior ambient light into the garage scene with the 50.0 multiplier. I thought this was a good way to increase the ambient lighting. Is this not good practice?

 

Just to check, I did a render with the previous settings where it was blowing out at 500 subdivs and a sample size at 0.02. It rendered with no blowout, but of course rendered considerably dark.

 

Should I be keeping the primary bounce at 1.0 and be compensating by adjusting the iso on my vray camera?

[BrianKitts]

Yes, either adjust your camera exposure..... or as you put it if you want to push more exterior light in, increase the exterior light itself, either your environment lighting, or put a vray plane outside your windows.

 

If you boost your primary bounces, it's going to do that for all light emitters and it looks like at some point it just blows out of control. Why this is only happening when you have your render elements active is something is still a puzzle.

[narino]

Good to know. Thanks for the help guys.