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Maniphest T46846

Render process becomes increasingly slower
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Description

System Information
Win 7 Home Premium Typ 64, nvidia GeForce GT 730

Blender Version
Broken: 2.76b f337fea
Worked: 2.74 000dfc0

Short description of error
After it has rendered 6-7 frames the process will be slower. The rendered scene is almost the same. There is no growing object in the scene. With Blender 2.74 it needed between 2:30 and 3:00 min per frame. With Blender 2.76 it needed between 3:00 and 4:00 min.

Exact steps for others to reproduce the error
Load a scene with an object tracking animation, that has a hair particle system, the two addons rigify and re-face from blender market and some connected effects in compositor. Dimensions on HDTV 720p. The object with 200 samples, rest 100 samples. Light path with Limited Global Illumination, Max. Bounces down on 6 and no other changes in the presettings. Render the scene with around 20 frames. Notice the increasing of render time.

Related Objects

Event Timeline

Nils Machens (NeroMcKens) created this task.Nov 22 2015, 9:56 PM
Nils Machens (NeroMcKens) raised the priority of this task from to 90.
Nils Machens (NeroMcKens) updated the task description. (Show Details)
Nils Machens (NeroMcKens) added a project: Render Pipeline.
Nils Machens (NeroMcKens) edited a custom field.
Nils Machens (NeroMcKens) added a subscriber: Nils Machens (NeroMcKens).
mathieu menuet (bliblubli) added a subscriber: mathieu menuet (bliblubli).Nov 22 2015, 10:10 PM

attach a blend file. The bug didn't appear on 2.74 with those 2 scripts activated and of the same version you used for 2.76?

Aaron Carlisle (Blendify) added a project: BF Blender.Nov 23 2015, 12:21 AM
Aaron Carlisle (Blendify) added a subscriber: Aaron Carlisle (Blendify).
Campbell Barton (campbellbarton) lowered the priority of this task from 90 to 30.Nov 23 2015, 10:41 AM
Nils Machens (NeroMcKens) added a comment.Nov 23 2015, 12:30 PM

Yes, the bug didn´t appear on 2.74 with those 2 scripts activated and of the same version.
Here is my blend file. The animation start at frame 865.

Cooky Prototyp 6.2 B.blend.zip238 MBDownload

Sergey Sharybin (sergey) added a subscriber: Sergey Sharybin (sergey).Nov 26 2015, 12:28 PM

Please make sure you don't have other scripts enabled by loading factory settings and see if it makes any difference.

Bastien Montagne (mont29) changed the task status from Unknown Status to Archived.Dec 4 2015, 4:42 PM
Bastien Montagne (mont29) claimed this task.
Bastien Montagne (mont29) added a subscriber: Bastien Montagne (mont29).

No news since one week…

Nils Machens (NeroMcKens) added a comment.Dec 5 2015, 5:17 PM

I´m so sorry for my very late answer, but I had very big problems with my work and no time to make a render test.
But anyway, here is my answer.
Yes, the problem persists with disabled scripts by loading factory settings on 2.76b. I have downloaded it as a zip file and ran it on my desktop. It needed much more time, around a minute, per frame and became more and more slow.

Aaron Carlisle (Blendify) added a comment.Dec 5 2015, 5:32 PM

Check to make sure that your computer is not getting too hot. Under your computer power management you can change your processor to run at a low percentage to prevent it from heating up .

Nils Machens (NeroMcKens) added a comment.EditedDec 5 2015, 8:06 PM

Thanks for the note. I render with CPU and MSI Afterburner shows me a temperatur of 66° C. Am I right that Fahrenheit is used in the USA? So it´s 150.8° F. I think this temperatur is ok, isn´t it?

Aaron Carlisle (Blendify) added a comment.Dec 5 2015, 10:34 PM

Looked it up this one website I found said that 60 C is the maximum you want to be at for long periods time. I would change your power management to keep your processor below 75%. If you get consistent render times after doing so I would recommend trying to clean your fans or maybe get better ones which are pretty cheap if you do not go over board.

http://www.pcadvisor.co.uk/how-to/desktop-pc/what-is-ideal-cpu-temperature-image-3498564/

See this page to see how to get to these settings see this web page and instead of setting to 100% do 75% or whatever keeps your CPU at a better temperature.

http://smallbusiness.chron.com/maximize-cpu-usage-57284.html

Nils Machens (NeroMcKens) added a comment.Dec 6 2015, 5:46 PM

Thanks a lot. I have change the settings and the temperature is below 60° C.

Aaron Carlisle (Blendify) added a comment.Dec 6 2015, 6:08 PM

Has that kept a consistent render time?

Nils Machens (NeroMcKens) added a comment.Dec 6 2015, 7:54 PM

I´m sorry. I don´t think so. Have a look at my Render Notes.

Render Notes.txt503 BDownload

Nils Machens (NeroMcKens) added a comment.Dec 6 2015, 8:02 PM

To synchronizing objects needed much more time on 2.76b. It was 6:27 min. You can´t see it in my notes, because the notes are from a second try.

Aaron Carlisle (Blendify) added a comment.EditedDec 6 2015, 8:02 PM

OH I miss read the report! You are reporting a regression I am sorry for my miss under standing. I have no more ideas however @Sergey Sharybin (sergey) may be more helpful

Nils Machens (NeroMcKens) added a comment.Dec 6 2015, 8:30 PM

No problem, thanks for your help.

Sergey Sharybin (sergey) changed the task status from Archived to Unknown Status.Dec 19 2015, 8:55 PM

There are two things here:

  • First one is forced particles re-distribution caused by bf8ea6b. This is a needed commit to fix and particles jitter. There's no real way to solve this automatically, you can just toggle hair visibility to force re-distribution and save the file.
  • Second issue is a bit tricky to nail down and it's still in the particles code. It's likely caused by same particle jitter changes which changed hair distribution, plus the code which ensures length of hair segment lengths. All those are needed for more stable hair physics.

Don't really see any regressions in the render code, it;s all in the particles which is a huge target for re-write for the 2.8x series. For until then wouldn't really consider this a bug, more like unexpected effetc caused by other fixes. It's probably possible to solve it, but would rather invest time in working on a new particle code. So thanks for the report, but it's something we have to live with for a while/