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Author Topic: flickering objects in renders (and a temp fix for it)  (Read 816 times)

cpember

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flickering objects in renders (and a temp fix for it)
« on: September 12, 2016, 05:00:44 PM »
Hello,

 I've been trying to debug a flickering render (NOT GI/sampling based isssue). The issue (a few have reported here) is one section of FP just randomly not rendering on frames on a renderfarm. By this I mean a single FP object that has a couple of mesh objects to instance will drop one of those objects at rendertime.

this thread: http://forum.itoosoft.com/index.php?topic=3979.0
and this thread: https://vimeo.com/180078948
are good examples of this.

 After a few days of trying to diagnose the issue, I think I know what is breaking. I started noticing the first X frames were completely fine during render, and the issue popped up after those frames finished and the *second* frame started rendering on the same machine. We use deadline here for render management and I was looking at the logs and saw we had a 2 minute setup time on the first frame a machine rendered, and a less than 5 second setup the second time they rendered. This seemed pretty normal considering if max keeps the file open/in memory and just skips to its next frame, there should be no setup. However, those second frames were missing objects. To test my theory, there's a deadline option (can't remember if BB can do this too) for reloading plugins every frame. requeued the job entire job, and no more issues. This is a temp fix, as it's VERY inefficient to force max to reload scenes all the time (our shots are usually +gb files here)

I'm guessing something is getting dropped during the cache/memory of the frames after the initial ones a machine renders, or it's not properly caching one of the object locations or something like that. So a temporary workaround is to restart the renderer between frames (reload plugins, it flushes all memory and force reloads max)

Just for the record it's rendering in vray (latest build 3.x) and FP 4.4.1 (I *think* thats the build, but I'm at home and can't remember the last .X . I'm getting the studio to upgrade to 5.x this week I hope) I'm with ScanlineVFX but I am using my own account to post (why this post isn't in the commercial section :)

hopefully this will point you to something that helps fix this issue. I can run a few more tests here if you need, I have about 2100 machines I can throw it on.

If you need to contact me directly for more info, just PM me and I'll give you my work email so you can get in touch.

Hope this helps a little bit,

cheers,

cp


Michal Karmazín

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Re: flickering objects in renders (and a temp fix for it)
« Reply #1 on: September 12, 2016, 05:10:32 PM »
Hi,

Would you mind to send us your scene to have a look at it here? Thanks in advance.

Best regards,

cpember

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Re: flickering objects in renders (and a temp fix for it)
« Reply #2 on: September 12, 2016, 05:19:27 PM »
I would love to, but it's a client/NDA thing, and i have no control over that :/ . I'm going to try and make a generic easily reproducable scene.

cheers,

cp

cpember

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Re: flickering objects in renders (and a temp fix for it)
« Reply #3 on: September 13, 2016, 07:46:36 PM »
we are using forest pro 4.4.1 here (just to be sure I had the correct version on the thread)