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Maniphest T69843

Commandline render takes too long synchronizing objects in cycles
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Description

System Information
Operating system: Windows-10-10.0.18362 64 Bits
Graphics card: GeForce RTX 2060/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 431.60

Blender Version
Broken: version: 2.80 (sub 75), branch: master, commit date: 2019-07-29 14:47, hash: rBf6cb5f54494e
Worked: (optional)

Short description of error
Commandline render takes a big amount of time synchronizing all objects in scene.
It seems to be just a matter of taking too long to actually PRINT the log to console, as per https://developer.blender.org/T62833.

Exact steps for others to reproduce the error

  • Factory settings
  • Create 3000 cubes (separate objects)
  • Set engine to Cycles
  • Save file
  • Press F12, just for cientific purposes. Buckets should start immediately.
  • Close Blender and run a command line frame render. Here is what I used:
cd %blender%
blender -b "path\file.blend" -f 0

It should take several seconds to synchronize from Cube to Cube.3000 prior to actually start rendering.

Related Objects

Event Timeline

Ricardo Drehmer (rdrehmer) created this task.Sep 13 2019, 3:14 PM
Jacques Lucke (JacquesLucke) lowered the priority of this task from 90 to 30.Sep 19 2019, 3:50 PM
Jacques Lucke (JacquesLucke) added a subscriber: Jacques Lucke (JacquesLucke).

Please prepare a .blend file so that everyone can reproduce the issue using the same file.

Ricardo Drehmer (rdrehmer) added a comment.Sep 19 2019, 3:58 PM

a.blend15 MBDownload

Sure! Here it is!
It's a file set for Cycles rendering with 3000 cubes.

Again, the command used for rendering was:

cd %blender%
blender -b "path\file.blend" -f 0

And, as per bug report mentioned above, it seems to occur on Windows only

Jacques Lucke (JacquesLucke) raised the priority of this task from 30 to 50.Sep 19 2019, 4:25 PM
Jacques Lucke (JacquesLucke) added a project: Cycles.
Jacques Lucke (JacquesLucke) added a subscriber: Brecht Van Lommel (brecht).

Can confirm the issue. The syncing takes about 20s for me when its printing to the Powershell on windows. Without the printing it is done in less than a second.
Maybe there should be a command line option to disable the printing? Or maybe it is faster to log everything to a file instead? I don't know what the best solution to the problem is.

Ricardo Drehmer (rdrehmer) added a comment.Sep 19 2019, 4:35 PM

I guess a single print of "Synchronizing objects" could be sufficient for a normal situation.
And if you need a print for each object (to see which one is taking too long, for example), one could enable a debug mode or raise the verbosity level up a notch.

Dalai Felinto (dfelinto) added a project: Tracker Curfew.Dec 23 2019, 1:50 PM
Brecht Van Lommel (brecht) changed the subtype of this task from "Report" to "Known Issue".Jan 27 2020, 12:01 PM
Brecht Van Lommel (brecht) edited projects, added Render & Cycles; removed Tracker Curfew.
Thomas Dinges (dingto) closed this task as Resolved.Nov 24 2022, 4:36 PM
Thomas Dinges (dingto) claimed this task.
Thomas Dinges (dingto) added a subscriber: Thomas Dinges (dingto).

Cannot confirm this anymore with Blender 3.4, total render time is 00:08.71.