I usually render still images with very high samples(1000-5000) in cycles render engine.I leave this rendering on my desktop PC overnight. I was wondering if there is a feature/addon that can save the rendered image every 100 samples or every 30 mins or something of the sort. So that when I wake up in the morning and there was a power outage during the middle of the render, I still have a render close to the quality I wanted rather than none.

  • $\begingroup$ I believe the "save buffers" setting in Render settings > Performance does something like this, however I haven't tested it. $\endgroup$ – gandalf3 Feb 17 '17 at 7:52
  • $\begingroup$ Maybe this answer is useful for you as well. $\endgroup$ – binweg Feb 17 '17 at 7:56
  • $\begingroup$ @gandalf3 I have searched all over the internet for details about that feature nothing comes up.Could you explain more on it. $\endgroup$ – Bob Kimani Feb 17 '17 at 8:49
  • $\begingroup$ @binweg unfortunately it doesn't $\endgroup$ – Bob Kimani Feb 17 '17 at 8:49
  • $\begingroup$ @Jamesup Unfortunately, after some testing, it appears save buffers does not do what I thought. It caches finished renderlayers to disk (by default in /tmp/blender_<random_hash>/_<scene name>_<renderlayer name>.exr) $\endgroup$ – gandalf3 Feb 17 '17 at 9:54

There is a trick that you can recombine images in post editing with blender. Then you can combine 10 images or so, (using animated seed settings).

So you render a still image as animation images with lower sample rates and recombine them. it takes a bit of manual work to recombine, render speed is slightly lower (bhv rebuilds between frames). for the rest doable. in the beginning some people hoped to reduce noise.

or in theory one could use this method to increasingly improve a real animation render if you store the images in different folders (by some scripting).

But you might also check the latest blender builds and the denoiser, unless you do a lot of diamont /glass reflections such a sample settings can be decreased a lot.

There is a addon/script that does this http://adaptivesamples.com/2013/07/22/progressive-animation-render-addon-and-image-stacking/

Most of all though i recomend to review your render settings, today a fairly reasonable render can be achieved with proper render settings: https://www.youtube.com/watch?v=8gSyEpt4-60

  • $\begingroup$ Although this is a good technique, am afraid it doesn't adequately solve the problem. Hopefully blender implements it soon. $\endgroup$ – Bob Kimani Oct 26 '17 at 7:27
  • $\begingroup$ well essentially changing seeds allows to recombine every 100th times sampled image, its the same to add image100+200+300+400 samples as compared to only saving an image 500 samples, there is a little overhead because BHV will be recalculated.. If your rendering a still image, you might render it with sample settings 100 then recombine the frames to one image, there has been a time people did this. But personally i found it a bit complicated to do (lots of compositor nodes to recombine images (averaging them out), it would solve your problem. but its kinda daunting to do in compositor. $\endgroup$ – user613326 Oct 31 '17 at 21:38
  • $\begingroup$ That's what I meant by it not being fully adequate, yes it solves the problem but it involves a lot of work, personally I mostly do still images. I appreciate the help but I wish there was a simpler solution, since this is just to avoid a power outage/computer crash . $\endgroup$ – Bob Kimani Nov 1 '17 at 20:38

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