Pause render suggestion-

I have a suggestion. Because I dont keep up to date, nor really know where to look within the blender developer forums, I am sorry if this a re-post, but before I carry on with suggesting it Id like to hear what others think.

Rendering in cycles takes up a lot of CPU power for me… it just does. When I am running a long render that takes an hours+ time, I dont always want to wait till night time to do it while I am sleeping, but also want to be able to finish things on my computer. I am wondering if anyone else has wanted a “pause render” feature that would drop thread usage temporarily so if you need to check something on your computer mid render, you can just pause it and avoid the lag, ghosting, rubberbanding, etc.

I dont know what all goes into cycles engine, however I do know that this is a common feature in most engines and it might be cool to see.

If this is in the works already than I wont proceed, but if this has the kindof following Id expect if others feel the same way I do, I would like to formally make a suggestion in the developer forums.

Just looking for your thoughts, and again, if someone knows if this is already in the works, or maybe if there is an existing patch for it that can be manually installed into blender…

There is a pause button in realtime viewport rendering. I can’t for the life of me not understand why there isn’t one for F12 rendering.

You can pause the process, see:

If your running Windows (or any OS with process priority :P) then simply set blender.exe to the lowest priority in the task manager.

Presuming you have enough RAM, this works quite well for me, I watch YT videos, game or program at the same time, and blender will only get CPU cycles that are spare, any other program will get them first if it needs.

I have 16gb of ram but my processors run full speed ahaid… and for good reason. I want them to. Some times I only need my computer for 6 second but its somewhat urgent and I am forced to stop the render, and I dont want to run on only 2 threads every time as a “just in case” measure… if you understand what I am saying…

from what I read there is no UI function for it and it relies on you using mac or linux… I am on PC and after experiencing ubuntus lack of support for my standard ATi graphics card, I really dont care to go back to it, again…

If this could be brought back to pc, some how and possibly given a UI function that would be AWESOME, though! Maybe even a way to adjust threads mid render so I dont even need to pause. That is what I do with lux. if something is urgent I just drop the threads down to 2 or 3 from 4 then when I am done set it back to 4 and walk away!

That doesn’t work for CUDA rendering (I don’t think I’ve ever tried for CPU rendering, but if you say so). But you can still pause a window render. Shouldn’t be that hard to put the same button in?

Thats the theory, but considering I have very limmited developing experience, mostly pertaining to ECMA, CSS and a little C#, I have been told I am wrong quite often of the difficulty of what seems like simple tasks. I am sure if I knew more about python and blender development that maybe I could make a more highly informed request, here, but I dont. I always get scared of that one developer who swoops in as soon as you say “well it can be done from the command line, so why not have a UI button” - “that is a lot of extra, needless difficult work. If its so easy, you do it!” and thats when I go… “S*** I really need to learn python!”

try search the page I linked for “Windows”

Oh, it was a separate program? I thought I was just stupid/blind when I couldn’t find it in Task Manager (where it really should be available). But still, having to rely on external software isn’t my idea of smooth integration of (imo) elementary functionality. Haven’t this been on the “todo list” for a while?

Still, thanks for the workaround, I have to test that.

I see, so you suspend the task… I also see that a UI button is in the to do list. Any idea if we will see that in any of the next up and coming .0X releases? or is it just not high enough of a priority that we wont see it till the next point release?

like luxrender we should be able to do multiple renders and join them later.i think this can be done with different seed values in cycles.

I am not 100% sure of that lux feature, as you described it. Perhaps I do. However, it sounds cool!..

I understand what your saying, and it appears you misunderstood what I said.

You still leave it at full threads, and it will use 100% of available CPU power. All that will happen is when another task comes along, such as your 6 second task, Windows will give priority to that task instead.

Via the taskmanager, you can easily change the priority of the Blender process at any time, as well as the number of CPU cores.

I understood what you are saying… but the problem remains that in my experience having all cores at 100% leads to my mouse jumping across my screen, applications rubber banding and explorer restarting occasionally. When I turn overdrive mode on in AMD overdrive so it runs all cores at 19X multiplier 100% of the time, apps open and run faster but my computer in general is slower…

Sorry, buy have you actually opened task manager, gone to the process/details tab (depends on win version) and set blender.exe to lowest priority?

It has nothing to do with changing AMDs overdrive settings, or altering your clock speed in any way.

I say this because I just tested it on 5 different devices, 2 with AMD processors and the systems all run perfectly with blender rendering on all cores.

It doesn’t help anything, at least not in CUDA mode which is what I’m using most of the time. Also I found, although slightly slower to complete, that progressive refine leaves me some additional computing power other than ESC to quit rendering. It’s not enough to watch anything on youtube or do something sensible, but at least it helps.

@CarlG, sorry yes it wouldn’t help for Cuda, only CPU rendering (which applies to the OP’s question)

It isn’t exactly what you want, but if you render the whole image (progressive refine or just one tile) then you can save an EXR in 32 bit. You can even save additional passes. With this you then just change the seed and start a new render when you want. Then combine those two renders in the compositor with a factor 0.5. This way you get the same as if you rendered straight that many samples.

@zeealpal: No, I mean my PC is coming to a crawl “processorwise” (like, 98% unresponsive), even if using CUDA. I don’t see with OP that CPU rendering is being used. Maybe it’s the graphics card that becomes overloaded and not the processor, in the end the PC is pretty much unusable regardless, until rendering is complete or I abort.

I never thought of merging halfdone images with different seeds, but most of the time I’m just doing tests (I’m a noob trying to learn). It’s a workaround that is not obvious to noobs. A pause button would be preferred, and much more elegant solution, considering it’s already available in viewport rendering.