Black Box Theatre Rendering - GI, Reflection Help

[logan683]

Hey, guys.

I have been struggling with getting some renders done of a theatre I do lighting design at in Fort Worth. It is a completely close black box (obviously), therefore WAY heavy in GI and reflections. I am using very specific IES files, from ETC, for the stage lighting.

I am including the colour output from the VFB with the info stamp. Also, the reflection and GI passes, respectively, as well as a zoomed in view of the areas I am have issues with from the colour, reflection, and GI pass. The GI pass exposure has been upped by +1 just to bring out the area a little more.

Specifically, no matter what adaptive setting I try, or the length of time I render, I cannot get a smooth reflection or GI pass out of this image. I am fully aware of noise issues in digital photography, but I would rather get a clean image than use that as an excuse.

I have been rendering RT GPU as production. I have used the default 1000 samples for GI, all the way up to 12000+ samples. I have used VMC to increase the reflection subdivs, at 64 currently, as well as the GI, up to 256, but admittedly, I am not sure if BF subdivs can be affected in that manner using RT GPU as production, given there is no setting in the VRay Render Settings when RT is used as production. The last render was 13.5+ hours and still not clear in the areas indicated in the images. VRay is the most powerful tool in my lighting arsenal, so I would really appreciate and be thankful for help with this.





https://www.dropbox.com/s/08vx1tuu3u...Mk-06.zip?dl=0

Origin Genesis Pro
-i7 4790K @ 4.5 GHz
-2X Titan X GPUs, 12 GB VRAM each
-32GB RAM
-Win 7 Pro

Thank you.

[Macker]

Looks to me light you're trying to remove noise from your render elements rather than the final output?!

[super gnu]

as far as i know material and light subdivs have no effect in RT? also when you talk about the gi subdivs, are you referring to the lightcache? i dont think youd have any benefit in going much above 2-3000, as its interpolated by the BF engine, so not directly causing graininess.

as macker says, you can expect more noise in your elements, since they are filtered in the final image (vray allows more noise in areas of the image that are not visible in the final image, f.e. in really dark areas) -your final image looks quite clean?

if you really wanted to get a noise free image/faster render, you could try making the black walls a lighter shade, then levelling it back closer to black in the final comp.

[super gnu]

also can i ask, what is your noise threshold set to?

[logan683]

Macker and super guru, firstly, thank you each for the replies and for taking the time to look my issues.

Macker, yes, that is correct and the way I know how to remove noise from the colour ouput (which is the comped image off all the individual passes). Grant Warwick's Mastering VRay has been essential for me, so I use that noise diagnosis method, which involves breaking out the GI, lighting, reflection, and refraction passes in order to find the source of the noise in order to adjust the appropriate pass accordingly to remove it.

super guru, the Max noise is set at 0.0, the default setting. I didn't think the reflection/refraction subdivs mattered using RT GPU, I just thought it might be worth a shot adjusting them. As far as the final image, my understanding was the individual passes, comped together, equals the final colour output. If I am wrong, I was not aware of it. Thank you for your input there.

As far as the leveling, I also thank you for the input there. What I am attempting to do, however, is reduce the amount of comping necessary. It's time I would rather use on other things, such as lighting.

As far as GI subdivs, yes, I meant LC. I apologize for not being specific on that. If the GI pass looks ok, are there any recommendations on cleaning up the reflection pass? I use VRayPhysicalCamera with exposure controls in order to get correct light intensities using IES lights, as this is, what I understand, the correct way of rendering IES lighting without having to mess with the intensities written in the file. I would think after 13.5+ hours on two Titan X cards, non-SLI, that is an issue, though.

Again, I thank you both for looking at this issue. I know your time is important and it is greatly appreciated.

Edit: Here are the render settings I am using currently. The GI was lowered, according to super guru's post.


Again, thank you for any and all input, guidance, and interest.

[super gnu]

well one of your main issues is a noise threshold of 0.0

its the most nonsensical default setting in vray as it leads to extremely long rendertimes.

try a setting of 0.005

this means the areas that get clean quickly ( your dark areas) will stop calculating, leaving vray to concrentrate on the problem areas.

anyway, if you dont wish to do comping ( and a levelling of the blacks id hardly call major comp work) then there is no reason to get your passes clean. if your rgb pass looks ok then thats all you need.

the passes are rarely clean in their raw form, as they are blended together to make the final image, and areas that are invisible in the final shot ( as in super dark areas ) will be visible in the reflection pass.

asking vray to clean these even though they are not visible in the final rgb pass( or comp using the passes) is asking it to do way more work than necessary, and frankly, pointless.

[logan683]

super gnu (apparently I can't read screen names correctly, so please forgive my earlier errors), I wanted to say thank you for the noise threshold setting advice, as well as explaining the passes. I was under the impression all the passes were filtered independently, but the filter is only applied to the internally composited colour pass, so thank you for that classification.

I have spent the past couple days re-working my scene and shaders, and testing with a noise threshold setting of 0.005 gives me a cleaner (or at least better looking) colour pass in a very bearable time. Just for fun, I let it go 20 mins, and it was clear as a bell. I'll post a result tomorrow, for posterity purposes.

Again, thank you for your time and advice.

[Richard7666]

well one of your main issues is a noise threshold of 0.0

its the most nonsensical default setting in vray as it leads to extremely long rendertimes.

try a setting of 0.005

this means the areas that get clean quickly ( your dark areas) will stop calculating, leaving vray to concrentrate on the problem areas.

anyway, if you dont wish to do comping ( and a levelling of the blacks id hardly call major comp work) then there is no reason to get your passes clean. if your rgb pass looks ok then thats all you need.

the passes are rarely clean in their raw form, as they are blended together to make the final image, and areas that are invisible in the final shot ( as in super dark areas ) will be visible in the reflection pass.

asking vray to clean these even though they are not visible in the final rgb pass( or comp using the passes) is asking it to do way more work than necessary, and frankly, pointless.

Abit off topic but I thought 0.01 was the default?

[super gnu]

not in vray RT. there its set to 0.0 by default. not sure why.. i cant imagine a situation where it would be the preferred setting.