Render after 8 hours looks grainy-

[inbelet]

HI,
one of my studnets is using vray 3.4 with sketchup 2016, she rendered a simple room for 8 hours on the progressive, on HIgh preset and this is the outcome:

any idea why is it so grainy?

thanks!

[Roju]

Please attach your file. I think she is using interactive render instead of production render, because there are two rectangles with less noise on the right side.

[inbelet]

It wasn't interactive, but progressive. can you think of anything else?

[GD3DESIGN]

Yes, to get help you'll need to attach the file, or at the very least, attach screen shots of all setting used (render settings, but lights as well). There are 100's of possibilities of what they're doing wrong here.

The two rectangular areas with less noise make me think that maybe they were using render region and just had a portion rendering instead of the whole image....though the regions are still pretty noise for 8hrs...

I'd recommend posting your vray render settings with all sections expanded so we can quickly see if anything obvious is standing out.

8hrs for a 800x600...definitely something wrong there.... Make sure there are not any emmisive materials lighting the scene. In fact, I would just turn of any emissive materials while trouble shooting the problem. Also, progressive mode is a no-no for final renders...should be used for tests & set up, then set to bucket rendering for finals.

Try resetting all vray settings to default and try a render on medium settings on CPU with Interactive OFF, and Progressive OFF, also switch from brute force to irradiance map (you'll need to up the irradiance map subdivs for final rendering, but default will do while trouble shooting problem).

[ValeroStudio]

That scene should take a half an hour at most even on a slow computer. Upgrade to 3.6 latest is my first recommendation. Then you need to bug hunt the issue - could be emmissive material on those lights I would think. Convert those to mesh lights.

[inbelet]

thanks, I posted it on a link here-
hope the link is clear enough

why is the bucket render better then the progressive?

[ValeroStudio]

no link

The bucket is showing you the final cleaned up version for that square. If you let progressive run to completion, it would eventually get there too with enough time - but 8 hours is nuts.

[Roju]

There is a mess in lighting. Please watch this and apply this knowledge for your scene. https://docs.chaosgroup.com/display/...ing+QuickStart

[Roju]

This image withous denoiser.

[GD3DESIGN]

Yes, definitely recommend watching all the quick start tutorials and come back if you can't get things figured out after that. The settings were a mess...everything is out of balance between different lights and global illumination and depth of field was on(turn that off for sure until you're a vray guru...)

I reset Vray settings to default, spent two minutes balancing the lights and rendered the 1920x1080 image below in 8 minutes. Unfortunately its Friday and don't have any more time....weekend deadlines are here!!!! But if you follow all the principles in Chaos Group's quick start tutorials, you should be on track. They are very well made (i would watch all, not just the interior one.) Don't be afraid to reset to default settings any time your render time or noise gets away from you...you should be able to set the settings in under a minute anyway. The default settings work pretty good. I generally switch to Irradiance map for primary GI, I prefer speed over 'physically correct'. As you set up your scene, take it one step at a time. Balance your exposure with just environment GI, then add one light at a time and balance each one. Keep your test renders on low settings with very small resolution. Don't start adding materials until your lighting is good and balanced with low render times. Take advantage of 'region render'. no reason to wait for the whole scene to render just to see if one light is blowing out the wall next to it, or if a material looks right.

Ok...back to work. Happy rendering!

[GD3DESIGN]

Oh yeah...it looks like your bananas might be getting a little funky.... Might want to eat those soon.

[inbelet]

Hey,
thanks for the render, but it doesn't help my student.

when I rendered it on my 3.6 version with progressive mode it took about 8 minutes, the result was not grainy and showed more light then the original photo-

But my student has 3.4 version,
1. why does her render is so grainy and takes forever?

2.why are the lights different between versions?

please dont tell my the solution is switching to 3.6, she has version 3.4.

thank you!

[ValeroStudio]

Well, the entire solution isn't to go to 3.6 but that's and old version with some bugs and you should always update if your student doesn't want to have issues when working with the engine. If your student has a legal copy then they should be able to upgrade to 3.6 with no issue. Just log into their account and download the installer.

Lighting setup aside, I touched nothing with the file, just downloaded and hit render and it took 5m 42s in Vray 3.6

Could be 3.4 or it could be the specs of the machine its rendering on but 8 hrs is an indication of some bug somewhere but it's not the model file. Their image might look different because they might have had corrections turned on in the VFB.

[inbelet]

Thank you!

[inbelet]

Can you elaborate on the differences between progressive to bucket mode?