On an unixoide system someone can halt and continue any process… not only via commandline but also with something like a task manager… or give a process a nice value (just work if nothing else want to)
… my windows time is long ago… and i never had a mac… but i think someone can do something similar on those systems ?
I don’t think you can use command line to pause and resume renders in windows. It might be possible but I have never heard of it tbh.
Here is also something via command line in windows…
That is awesome. Maybe Blender devs can be able to incorporate this into Blender in other to pause and resume renderings?
Based on your previous requirements and use cases, like power loss, etc then that wouldn’t do what you want.
That means the software is still loaded, user still logged in, and PC stays fully powered. In simple terms one is telling running processes to basically stop running and just hold it’s current state. Then you can do other stuff at basically full speed and once done, tell Windows to continue the suspended process.
It’s not saving the mid rendering, like vray does in that previous link. You lose power and it means you start all over again.
Then there’s the question of if it would in fact work. That software is suspending a CPU process, but if one was GPU rendering, then I’m not sure how well it would work, if at all.
Isn’t this what UPS (not the parcel service) are for… ??
@thetony20 Thanks for the explanation. 
Well, it wouldn’t work then.
@Okidoki Nah… Not for high end rendering. The UPS battery is derinitely gonna weaken over time. UPS isn’t supposed to be for power backup for a long period of time. Depends on how long the power outage is.
I don’t know why we are assuming power outage is the only reason we need a pause and resume. This exist in other renderers and if Blender devs can add it without any issues, then it should be a thing.
People who use other renderers use it so if its not going to be a problem to add. They should add it. Its that simple and I doubt it would affect the speed of Cycles X or its continued development.
If they don’t want to add it. Thats also their decision but I don’t think their adding it will affect Cycles X’s development from what @Ace_Dragon mentioned. 
I wouldn’t assume the triviality of implementing a particular feature.
By all means make a right click select proposal and see if it gains traction. That usually the best way to ask for a feature.
in the meantime cycles already has a “sample offset” option. If you want to pause and resume a render, you could stop and save your current render, note how many samples had been processed, and then do another render later starting with that sample offset. (I wonder if just changing the seed would also be sufficient) Then you can combine them in the compositor or any image editor. For best results the mix factor should be the ratio of the sample counts of each pass
I believe power outages are being focused on because you brought it up; and then asked if the reason the feature wasn’t getting more interest was due to fear of competition by artists in third world countries…
It also applies here in the US during severe storm season. The plains states including Kansas have a historical reputation for having some of the most violent weather in the world, so my computer used to flicker off during the Spring and Summer before I started using a UPS.
I did bring it up but that became the main focus when there are other reasons I mentioned.
No, that was directed at the person I was having a conversation with not why the feature wasn’t getting any interest. You are trying to make it sound like it was a generalized comment I made.
You can follow the progress on this feature here: https://projects.blender.org/blender/blender/issues/92569
So what is a real “pause-and-save-data-and-resume-later” good for ?
( and this is not just an image… and extra data maybe saveable in an EXR file… i don’t know if any structure generated in the render process can be re-initialized later or it also have to be saved…)
If someone does render any scene then one want the final result in no time… so why stop inbetween ??
If you want to check the already computed result… then it is not final but in progress because someone may want to change mind about something…? Or just continue… But you can do this by looking at the Render Window (even screen shooting this)…
( Regarding UPS… you may want to think about how big institutions do secure their computer systems… they do have diesel generators… and if all this is just too expensive… then: Renderfarm )
One idea i do have is: if your rendering is done in a virtual machine… then this can be halted and saved for later resume… (and this may include GPU usage ?).
Anyway… just because some app do have some feature i don’t think any other app must have this also… again: (wo)man power is needed to accomplish this… and then also: it has to be working… if a render halt breaks the comutation then there are thousend of users complaining again… so:
So what is it good for ? Solving problems someone has in the workflow or the infrastructure is not the task of the blender devs…
( And don’t tell XY has this so it must be easy… because then: use the source, luke… )
Hi, two examples were Pause is useful.
I use Octans for some time and this was really helpful sometimes.
Cheers, mib
If you want a render fast… then don’t stop it… if you want to do something else with your computer… don’t start to do it something else…
…this is like to have one’s cake and to eat it two ( ← just learnt this saying in english )
Again: lack of resources…
→ use another computer or renderfarm…
→ not the problem of blender devs…
So if someone doesn’t have problems with powersupply… then just halt and resume the blender process as mentioned above…
Lack of resources is standard for small studios or single artists, this is one of the reasons they use Blender.
The problem of developers (not only Blender) is not listen to the user.
I mention the blocking of the UI, there was a patch to handle this but rejected because older GPU don´t work with it.
This should not be a problem for the Blender devs, the user can buy new GPU´s. 
So blender has to solve this problem… i do think this is wrongly thought through…
Somene can’t take a delivery job right now if he is already somewhere delivering something elsewhere… a delivery company has to have mutliple delivery vehicles or also the possibility to rent additional drivers and vehicles… but anyway if all employee is working right now… you just can’t take the job because you will fail to deliver in time…
…so if you are a single person company… then you just can’t do everything… and you also can’t blame anybody to solve this/your problem to be incapable to make this delivery job…
( And of course it is very easy to say that something should be no problem for someone else to solve your own problems… )
…and by the way: any question about making something faster is also contradictory then… making it faster and then suspend it…
Again: If your only computer is engaged doing this renderjob then there are renderfarms which you just pay while using them… and nobody should be blamed to solve this specific personal problem (except you pay for it… ohh… but you are in lack of resources… money… )
I think this discussion will not lead to anything… if there is no running water availible and if your bucket is to small to take more water then you have to go multiple times… or buy a bigger bucket… ( until you can’t lift it anymore ) and any complaint about wanting running water are useless if there is no water supply companie where you life and/or you don’t pay for it… saying “someone should” doesn’t help you…
On the other side: there were now some possibilities mentioned…
Great to know its been worked on and will be part of Blender Cycles in future. Thanks for the info.