Can't finish a single frame render

[radvfx]

Mac OS X Mojave
V-Ray: 4.03.03.0001 (Feb 2019)
Maya 2018

CPU render (either Bucket or Progressive).

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I have two issues, one with each possible renderer in V-Ray:

Buckets: the black bucket issue.

I have tried "raising" the AA (from default of 2 to 4), didn't work.

I have tried changing out the older texture calls (asset originally created with V-Ray 3.52.03.

There are the only two "solutions" I have seen posted, and neither worked in my case.

The rendering indication at the bottom of the Maya window gets to 99% and stays there.

The timing estimate on the V-Ray frame buffer gets to a number (probably the number where the image should have completed) and stays there.

Current render time on the VR buffer says 3h 49m 5.9s and estimates completion time to be two minutes later, but the render was started 14 hours ago.

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Progressive: the limiting values to cause a frame to finish do not seem to work the way they are advertised.

My understanding is that: noise threshold, max subdivs and time in minutes are used to complete a render in Progressive. The idea
being that if one of these parameters is met, the render will complete and move on to the next render layer when started with the Render Sequence
menu.

I tried getting an estimate of how much time to allow for a render.

I had these values: max subdiv - 2, noise threshold - 0.1 and time at 10 mins.

I rendered a 1280 x 800 version (1/16th of final) of my image, it completed in 12 minutes.
16 x 5.5 and a final version with the same quality should take 192 minutes.

I decided the final image needed to look a little better, so I double my noise threshold to 0.05.

I assumed that this would effectively double the samples needed and moved my render time to: 384 minutes for final.


I set up a render for this and went home. The next morning the render had not completed (14 hours later).

Time estimates for production are critical, and I have looked online and through the ChaosGroup Forum for suggs on either
render sollution, and so far, almost no real-world docs about what settings actually do to render times.

If you have any, I would appreciate your experience and insight. Thx.


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I'm new to V-Ray and I'm certain that I am making poor assumptions at this point, but I have 33 years experience with
RenderMan, 12 years experience with Mental Ray and 5 years experience with Arnold. I have never had an image that
would not complete.

On the forums, I see a lot of references to the "Black Bucket" issue, the earliest I've come across being a 2012 posting, but few suggested solutions.

I have a deadline and this has been a problem for 5 days, and I could not post before today.

Who can help me?

- Jim

[glorybound]

The only black bucket issue I know of is missing texture maps, which is a path issue. I am on MAX and a PC, so your issue might be different. Today's V-Ray, all defaults are the way to go, so maybe reset your render engine to standard and back to V-Ray and try the defaults. Are you using NEXT?

[radvfx]

Yes, currently using V-Ray Next for Maya, hotfix 2 (v4.03.03.00010) from Feb. 2019 per client request.
Maya 2018 as well.

Is there a simple way to set V-Ray back to defaults or do you just have to know them?

BTW, very simple scene, maya file, 2 bump maps and 1 OSL file. All are present and I have no errors or warnings for missing files.

One thing I noticed early on, the machines we are using at work at Intel Xeon E5 chipsets, and I believe the Embree calls are not really compatible with them, so I turned off the chipset RT assist early on.

- Jim

BTW, thank for trying to help, I really appreciate it.

[radvfx]

Okay, Progressive render time estimates. When I render something at 1/16th res, it takes X time. I ASSUME that if I render something at FULL res (16 times larger, 4 times larger in X and 4 times larger in Y output) that the final render will take 16 times longer or 16X. I'm not seeing that behavior.

Currently, I have my limiting settings set to this: max subdivs: 2, noise threshold: 0.1, time: 90 minutes

My render just hit 90 and now is is still renderering.

How should I be doing my estimates?

Thanks.
- Jim

[glorybound]

Setting to standard and back resets V-Ray. I haven't touched a V-Ray setting in at least a year.

[radvfx]

Looks like the culprit might have been memory. 64 Gbytes wasn't enough, so, I will set bucket size (Render Region Division) smaller and re-try.

[glorybound]

That's a lot of RAM. I load my scenes up with all the bells and whistles and I don't go over 20MB.

[radvfx]

Right. I'm not using caustics or GI and BAM. Even with 16x16 buckets, I'm seeing 35 Gbytes on a 5K image.

[glorybound]

I would start troubleshooting. Override material with displacement off is a good place to start.

[yolov]

It might be (in theory) that you're hitting a place in the image where something's requiring a lot of momery and you machine starts swapping memory to disk, which is a very slow process.
Try these two things:
- set the dynamic memory limit to 0 in render settings > Settings tab > System
- lower the default subdivision and displacement subdivs in render settings > Settings tab > Default displacement and subdivision // the default 256 might be too much for large resolutions and something like 16 or 32 might work better

[radvfx]

Yolov,

I will try your suggestions. I still have about four buckets that do not complete in a recognizable time (way out of the estimation curve - more than triple), and one bucket that simply will not complete at all. The other spots re-rendered quickly with a simple "spot" render in the VRay FrameBuffer window. Then, I was able to save using the multichannel save to exr.

Perhaps your suggestions will bring the next renders into line with good estimated finishing.

Cheers and Thanks,
- Jim

[glorybound]

If something is over bright, buckets can get stuck.

[radvfx]

What do you mean by "overbright," Glorybound? Do you mean values outside of normalized color space?

[glorybound]

Overexposed pixels

[SonyBoy]

It might be (in theory) that you're hitting a place in the image where something's requiring a lot of momery and you machine starts swapping memory to disk, which is a very slow process.
Try these two things:
- set the dynamic memory limit to 0 in render settings > Settings tab > System
- lower the default subdivision and displacement subdivs in render settings > Settings tab > Default displacement and subdivision // the default 256 might be too much for large resolutions and something like 16 or 32 might work better

Isn't it time to increase the default setting of 5Gb of RAM in the Vray settings? I often forget to increase this in new scenes (or, more usually, set to 0) and it's rather low by modern standards.