Rendering very slow when screen is turned off (Mac)

[lcrivell]

I have a problem which is pretty difficult to analyse.
For all my renders that contain a specific plugin, and with VRay, the render of each frame takes very long when the screen of my mac is turned off, and as soon as I move the mouse again, then the render times get fast again.
If you look at the attached picture, you will see the render times: 11 minutes per frame when screen turned off, 1 minutes when on. Any idea how I could diagnose this ? Exporting the scene to vrscene gives me exactly the same performance issue.
Is there a way I can log anything to see what specific process is really taking long ?

Thanks !

[yolov]

What is the specific plugin that you're using?
I tried a quick test here and the render times were consistent with the monitor on and off.

Is there anything in particular that might be causing this like the monitor being switched off automatically bu the os after a certain amount of time? Although that shouldn't have any effect on the render times.

Also what resolutions are you rendering at? Can you try writing out to a vrimg and turning off the memory buffer to see if that makes any difference (it is usually used to save on memory usage when rendering at extremely high resolutions). (choose the vrimg image format and then the memory frame buffer option will be enabled where you can choose "none" - it is further down in the common tab where the vfb options are).

[yolov]

Could you also tell us the exact OSX / Maya / VRay versions?

[lcrivell]

Hi,
I am using VRay 3 Beta on Maya 2014, OS X 10.9.2. However the same issue happens with VRay 2.40.
The plugin is Miarmy, and I just perform a distributed render to analyse the output, and here it is:
Screen ON:
[2014/May/16|20:28:20] Compiling geometry...: done [ 0h 0m 0.0s]
[2014/May/16|20:29:01] Rendering image...: done [ 0h 0m 40.6s]

Screen OFF:
[2014/May/16|20:29:01] Compiling geometry...: done [ 0h 0m 0.0s]
[2014/May/16|20:40:10] Rendering image...: done [ 0h 11m 9.1s]

Can I put it as more verbose ?

The screen is turning off, as standard screen Standby functionality on the iMac. Resolution is pretty small, 720p. When I press on a key and the screen turns on, I often see the Maya status at "Updating frame at time xx". Not sure what happens during this step.

And last but not least, I've tested the vrimg and no-memory frame buffer, with the same issue (see attachment).


Thanks for your support !

[xxc]

May be something to do with the "app nap" thing introduced in maverick.... have you turn it off for maya?

[lcrivell]

May be something to do with the "app nap" thing introduced in maverick.... have you turn it off for maya?

Man, you're my hero It works now !!
Thanks.

[xxc]

You're welcome

[yolov]

Could you expand a little bit more on this, so it would be helpful for other users reading this thread?

Thanks in advance.

[xxc]

ok... the "App Nap" technology automatically slow down process that are not graphically viewable by the user (behind an over window, or when screen saver go on, etc...). It is done to save battery time so.... not really usefull on a mac pro
You can prevent an app to be slowing down by this feature in the "read info" of the app. Juste check the "dont use App Nap" (or something like that) and voilà...

[yolov]

Thank you for the clarification. Hopefully this will be useful to other people viewing the thread.