Welcome to Fractal Forums

It would be great if a render could be paused and resumed

I agree that would be a wonderful feature!

There is a work-around to imitate that functionality and depending on why you want it, it may work for you.

If you want to pause because it is eating resources and you wish to multi-task, you can (in windows) open your Task Manager and set the program's affinity to not use 1, 2, or 3 of your cores.  That frees up processing power for other things.

Alternatively, if you worry about running the machine too long or too hard and want to avoid overheating, you can simply put it to sleep (or hibernate) and the render will resume when you turn the machine back on.

I know neither of those are the same as a real pause feature, but until such time as that is implemented those work-arounds come in handy for me!

I often have 2 fractal generators and a 3D Art program all rendering at once on a 4 core machine.  I assign each program to use a single core and have the remaining one free to go online, work on my writing, or even play a low resource-intensive game and the other programs all keep doing their thing without interfering with what I want to do (or each other!).

Hope that helps...

Most UNIX-like systems support sending signals to processes to control their behaviour, using the "kill" command.  The -STOP signal pauses the whole program, while -CONT resumes it.  On GNU/Linux I use "killall" to control all the threads in a process at once (check the manual pages for your OS, especially Solaris has different behaviour iirc).  You can also adjust the process priority with "renice", or a process monitor like "htop" - I tend to make long-running render jobs have maximum niceness (19) so that everything else is prioritised.  Note: you have to have more privileges to reduce niceness (even if it was you that increased it before), as you can lock up the system if you're not careful.

Of course, this doesn't apply to Windows, which has it's own ways of doing things.

I agree, and was going to ask the same.
It would be nice also an autosave feature.