Is there a render time limit ?

Message boards : Number crunching : Is there a render time limit ?
Message board moderation

To post messages, you must log in.

Profile ChameleonScales

Send message
Joined: 2 Apr 16
Posts: 147
Credit: 1,120
RAC: 0
Message 14501 - Posted: 31 May 2016, 23:18:23 UTC

Sheep it is limited to 20 minutes per frame on a quad core. When taking longer, the project gets blocked.

I know BURP can at least render several hours, but is there a limit ?
ID: 14501 · Rating: 0 · rate: Rate + / Rate - Report as offensive     Reply Quote
Profile Janus
Volunteer moderator
Project administrator

Send message
Joined: 16 Jun 04
Posts: 4574
Credit: 2,100,463
RAC: 8
Message 14503 - Posted: 1 Jun 2016, 15:32:57 UTC
Last modified: 1 Jun 2016, 16:05:57 UTC

BURP is for bulk rendering. We have a massive startup overhead for each session (read: sometimes days!) but make up for that in compute capability. At some point another BURP-based site actually had a rule saying that sessions had to use at least X minutes of rendering time in order to be accepted.

There is no set rule or limit - only a soft limit to how long we will run a single part (of a frame) which is around an expected 8 hours and an actual hard cut-off time of a couple of days of time on a modern multi-core machine. Currently two sessions are running which may hit that cut-off because they couldn't be split into parts. Generally we try to keep parts within the 1-4 hour ballpark area if at all possible.

Apart from that (no pun intended, of course) the sky is your limit. If you can manage to use the frame-splitting feature and your target resolution is high enough then you could potentially hit many CPU years of compute time per frame.

The hardest session we have rendered, so far, was around 108 CPU days per frame and had 175 frames. The longest session was 92783 frames. The highest frame split was 300 parts/frame. The largest frame was 17280x17280.
We are limited to at most 2147483647 frames per session and 99999 parts per frame but there are some rules for how to use parts that rely on the resolution of the session. Also, presently no more than 256MB of zipped result data per frame (that limit is mostly relevant to multilayer HDR EXR rendering).
Someone tried to render a 55118 pixels image once, but Blender kept crashing on it, so we don't currently know the exact limit on the resolution that we support.

Of course it is also a balance and sessions are validated by a human being using common sense before being accepted. If someone puts in 999999999999 in the sample target field on a Cycles session for no other apparent reason than to burn CPU hours then that session will very quickly disappear from the session queue.
ID: 14503 · Rating: 0 · rate: Rate + / Rate - Report as offensive     Reply Quote

Message boards : Number crunching : Is there a render time limit ?