Bucket taking forever.

[gregvfx]

Hi,

I have again these buckets that seems to get stuck rendering for ever. Only on a few frames, only a very few buckets. But of course I need these frames for my animation to be completed...

The annoying thing is that you can see the image almost completely rendered on the farm and because of one single small bucket never ending computing the whole image goes to the trash bin...

Last time I had this problem with MR and solved it by switching from raster to raytrace or scanline on the missing frames... The per pixel difference wasn't noticeable.

It's on the shade map render pass of a stereo animation with Vray pattern objects. How can I fix this?

[tashko.zashev]

Hi,

There was a very similar issue with V-Ray and ForestPro in the past.
Which V-Ray version you are using ?
How complex is the scene ? Are you able to replicate this issue easily on a specific frame or it happens randomly?
Can you try to to increase the Secondary ray bias parameter and perform a test render again?

You can also send us the scene file and instructions how to replicate the issue in our environment to support at chaosgroup.com

[gregvfx]

Well it is quite random. The working frames are already taking ten hours to render... The vray pattern objects seem to be the problem. The scene is quite small in memory usage, less than 9 Go. But it is not rendering as fast as instances... I use to try scattering particules and use vRay instances but my setup in Pflow was working with a smaller number of particles, with the number I need for the final thing it was flipping the orientation of the particles that is based on uv gradients vectors.

I reduced the size of the buckets in hope to ease the process for vray and will see how it goes tomorrow.
So frustrating as the frame that works look very good.

Maybe it has to do with retracing the lightmap...

[vlado]

If you can create a few crash mini dump files using Process Explorer and get it to me at vlado@chaosgroup.com while a machine is stuck in this way, it will be very very helpful to figure out what the problem is.

Best regards,
Vlado

[gregvfx]

Oh ok! I need to install something on the render node, no?
Can you guide me through this process, I would be glad to help as it would definitely help myself too!

[vlado]

Sure, download and run process explorer from Microsoft:
https://technet.microsoft.com/en-us/.../bb896653.aspx

Then, when you get a stuck bucket, in Process Explorer, right-click on 3dsmax.exe and select Create Dump > Create minidump... (be sure to select minidump and not full dump - the full dumps are very large).

Do this a few times and email me the resulting .dmp files to vlado@chaosgroup.com

Best regards,
Vlado

[gregvfx]

Did you have time to search the minidumps?
The difference between render times is going from 1 hour to 33 when I left the office yesterday...
No noticeable differences between the images...

Stopped the job as nothing happened after 50 hours of render time...
Trying to increase the minimum subdivs and see how it goes...

[leotchest]

Hows this going ? Over the years ive often suffered from this problem with the final buckets of a rendering just getting stuck or going to slooooooww. Usually they do eventually finish but they take an inordinate amount of time which is crazy frustrating when your in a hurry to email to the client a progress render.

[vlado]

That's where the progressive sampler is very very useful. It doesn't have this problem and you always have an image to show.

Best regards,
Vlado

[leotchest]

I find that method too slow - but since you mention it i will try it again

[cheerioboy]

I find that method too slow - but since you mention it i will try it again

I also haven't switched to the progressive sampler yet. There's something satisfying in getting the final image in a bucket, so you know the rest should be ok. Than waiting for the whole image to resolve itself. And what about DR, it can't half as satisfying with progressive rendering when you aren't getting alllll those buckets!

[leotchest]

Its pretty good - i will start using it from now on It would be good to have more feedback information per DR slave