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Okay, so I've been working on a living room scene for a bit, now I want to render. Everyone online is saying it's a good idea to use 1000-5000 Samples. So I set it to 1000 and my render time for a single frame will take around a year... So I compromised and set it to 100. Rendering a single frame took 12 hours:

enter image description here

Am I missing something completely? I'm rendering with a GTX 1060 6GB and an i5-4460. Here's my sampling settings:

enter image description here

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    $\begingroup$ it seems that you are using volumetric shaders, they are very heavy to render. for that reason, many people choose to add volumetric effects in post-production. try to remove them and give a test render of something around 500~1000 samples (you could try to lower the resolution for testing) $\endgroup$
    – arvere
    Commented Dec 8, 2016 at 15:19
  • $\begingroup$ @arvere Is there any method of baking volumetrics? I plan on using this scene for an animation (Which I know will inevitably take a long time to render, but I got that handled) $\endgroup$
    – Josh Silveous
    Commented Dec 8, 2016 at 15:44
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    $\begingroup$ There is no answer to 'how many samples should I use' because that changes depending on your exact scene. $\endgroup$
    – Ray Mairlot
    Commented Dec 8, 2016 at 16:00
  • $\begingroup$ @JoshSilveous as far as I know, there isn't, but I'm sure there are a lot of ways to fake it. you just have to search for it $\endgroup$
    – arvere
    Commented Dec 8, 2016 at 16:26
  • $\begingroup$ @arvere You can fake it quite simply by creating a mesh in the shape of the volume where the "sunlight" is passing through and add an 'emission' shader connected to the Volume node. If the light is pretty much parallel (as in the example picture - since it's effectively sunlight from a distance source) then that's all you need to do. However, if it's from a more local light source so it is spreading out then you can include a gradient in the Emission strength so that it falls off as it spreads out. $\endgroup$
    – Rich Sedman
    Commented Dec 8, 2016 at 16:44

6 Answers 6

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That's about right for something with that many samples =)

You have square samples enabled so it isn't 100, but 9,216 (96 x 96) samples. You should be playing with other things to get the render times down:

  1. Clamping...you are already clamping indirect some, but also try clamping direct a bit.
  2. Try the other performance/sample settings such as filter glossy
  3. Disable all caustics if you don't mind the impact in your image
  4. Reduce the number of bounces for things like glossy and diffuse (especially glossy)

Here are two good articles filled with more tips:

http://www.blenderguru.com/articles/4-easy-ways-to-speed-up-cycles/

http://www.blenderguru.com/articles/7-ways-get-rid-fireflies/

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    $\begingroup$ So when people say use 2500 samples, the settings I should use are 50x50? $\endgroup$
    – Josh Silveous
    Commented Dec 8, 2016 at 15:42
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    $\begingroup$ @JoshSilveous Yes. You can uncheck the 'Square Samples' checkbox and then simply enter the number of samples in the Render Samples (ie, 2500 in your example). That 'Square Samples' just causes confusion IMO. $\endgroup$
    – Rich Sedman
    Commented Dec 8, 2016 at 16:39
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There is no "correct" number of samples to use. Usually the rule is to use the smallest number possible that yields a noise level that is acceptable to you.

For the most part think of it as finding a balance between the resources available to you in terms of computing power, time spent rendering and artistic goals...

Any time you are dealing with volume scattering the image will get noisier, and you will need to use more samples to minimize it.

There are a few tricks out there to minimize noise, like using branched path tracing, light portals, sometimes clamping.

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That depends of the final use (and the style of texturing): - when I render for a single image, in 4k resolution, I'll use 250 to 500 samples, sometimes 600 or 700 but it's occasional! - if I render for an animation, always in 4k, often 150 to 200 samples are enough...

And the tiles size are very important, with my old GTX660Ti 3Gb, the best size is 256x256, with a less or more value, the render time increase!

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  • $\begingroup$ I commonly use 256x256, its just with this specific scene blender crashed when I tried that, so I lowered it to 128x128 $\endgroup$
    – Josh Silveous
    Commented Dec 8, 2016 at 15:44
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Since Blender Version 2.79 there is finally the "Denoise" feature!!

In some cases now e.g. for 1920 * 1080 pixels only 100 samples gives me better results with Denoise enabled then rendering the same Scene with 1000 samples.

enter image description here

This reduces the render duration to 1/10 while the result is even better!

This first image was rendered with 1000 samples without Denoise enabled (render time about 20 minutes):

without denoise

This second image was rendered with 100 samples and Denoise enabled (default settings) (render time about 2 minutes) with denoise

The result is basically the same but especially in the blue parts you can see that the second image has even a better quality though rendered in 1/10 of the time.

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    $\begingroup$ I'd be carefully to say, that your denoised example has an "even a better quality" than image with high samples. Although I don't know your model, the denoiser seems to have introduced new artefacts, which are going to flicker in animation. $\endgroup$
    – Leander
    Commented Jul 29, 2018 at 13:48
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    $\begingroup$ @Leander yes ofcourse this might be true for animations .. but for a single image this is a huge improvement anyway $\endgroup$
    – derHugo
    Commented Jul 30, 2018 at 7:39
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You have probably already received the answer for this but you have squared samples switched on which means (I think) that you are actually using 96 x 96 =9216 samples! When you had it at 1000 samples it would have resulted in 1000,000!!!

If I am rendering a potentially noisy interior still image, I will then use about 15,000 samples. This is probably regarded as complete overkill - but it works for me!!

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Here's what I prefer. Glossy tends to be noisy, that's why it gets a few more.

RenderSettings

Some scenes don't need that many, you can get away with dropping it down to 64 or 50.
Some are worse than others, so 128, 150, or even 200 AA looks better.

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