Can anyone tell me why it takes 48 hours to render a 12-second animation in Cycles (in Eevee it takes about 2 hours)?
I’ve just started learning Blender and don’t understand what settings to use for rendering. All textures in the scene are max 2k (changed using a Python script). Can anyone please help? The screenshots show the settings I’m currently using.
How many samples are you using, in your screenshots the sampling menu is closed? You mentioned it is 12 seconds, but how many frames is the animation, I am guessing it is 288 frames if it is 12 seconds at 24 fps?
Would it be possible for you to upload your Blender file.
If you mean “render → samlpes”, then 250.
At 250 samples the actual rendering shouldn’t be taking too long, would it be possible for you to share your file.
Assuming you have 288 frames at 3 minutes each, it should only take 14 hours to render the entire animation, not 48 hours.
When you press render does it spend a long time loading before it starts rendering?
Here you go. Rendering this scene (1 frame) took 3 minutes. Dropbox
Looking at it, your scene is relatively large with lots of large materials, this will likely be affecting your render time.
You could try lowering the quality of the materials, removing unneeded objects, or lowering the samples.
For this size scene, with this quality of materials and objects, I think 3 minutes per frame isn’t too bad, but with 700 frames, it will take a long time to render the entire scene.
OK, so you are new to this… Well, 48 hours is absolutely awesome time for an animation render! It means you can render it over a weekend on your hardware. This is great news. It’s not actually a long time for rendering an animation. A long time would be 100 days for example. Then, you would have to use a render farm. There is absolutely nothing unusual about a situation like this. Maybe the only unusual thing is how fast it is. Welcome to CG.
This scene is slow because of the volumetric clouds, those are expensive to render. There are some ways to make it faster.
1- Reduce the volume settings in Cycles.
Go to the volume section of the render settings. If you are in Blender 5.0, check the “biased” checkbox to get the old volume settings, because they are faster to render and can be adjusted and reduced (if you are in an older version, these old settings will be the only option).
Then, see if you can increase the step rate and decrease the max steps without too much visual impact.
2- Reduce the render resolution.
Do you need such a high resolution for your use case? Remember that resolution is exponential: doubling the render resolution multiplies the number of pixels by 4 and the render times by as much.
3- Use Eevee instead of Cycles.
Cycles is really slow with volumes, especially when they are wispy and textured like this. This is a pretty simple scene, Eevee could give you almost identical results with a bit of setting adjustments.
This is Eevee, 1280x720, took 5 seconds on my RTX 5060. Your full resolution would be longer, but probably still under 30 seconds.
Here are some render settings to change to make it look better and render faster. I also darkened the color of the clouds in their materials, as they were brighter than in Cycles.
Your Eevee settings were altered from the defaults. Did you attempt it but didn’t know how to use Eevee?
4- Split the clouds in a separate render pass.
If you do still want to use Cycles only, something that can help is to render the volumes separately from the rest. Volumes interfere with the denoising process and will look better with fewer samples if they are denoised separately from everything else.
This is quite a bit more difficult than the other methods I showed, so I will link a tutorial. This one goes one step further: it renders the solid objects in Cycles and the volume in Eevee. But this trick can also work and be of benefit using Cycles for both layers, as you would need fewer samples for a good result.
If it makes you feel better, I render with a 2013 I5 with integrated graphics. I try not to get too ambitious…
There are all kinds of tricks to simplify the process. I don’t know most of them.
I think a pretty big one is: If you’re doing shots where the camera is sitting still, you can render still portions (like the background) and then render the moving foreground stuff separately. Of course there may be lighting details preventing that, but…definitely more efficient if you can work with that restriction.
Okay, thanks for the advice. It’s just that I’ve seen some people on YouTube rendering relatively complex videos (with weather effects and animation) in a few minutes on an RTX 3070. And Grok wrote that with my hardware, this scene should render in 20-30 minutes. So I decided to find out if there might be some problem with my settings. I just need a resolution of 2K, and I like Cycles because not only is the image better, but also, for example, my “fireflies” can illuminate objects, whereas in EEVEE they just glow but don’t illuminate. I’ve only just started learning Blender, and so far it’s difficult for me to figure everything out.
Cycles can be fast with your hardware, you just happen to have a difficult edge case here (complex volumes).
One more option I could suggest if you must render something difficult is to look at Sheepit. It’s a website where you can use other people’s help to render your projects faster. This is done at the cost of first helping other users with their renders. Thanks to some generous users, you actually get much more rendering power out of it than you have to give (and you can just let the service render your projects without having to leave your own computer running).
AI is of limited use for information about Blender, at least for now. It’s good at finding tutorials and existing information on the Internet, but it doesn’t have direct experience using it, it can only rely on what’s written about Blender. This is fine for general info, but can fail to understand complex situations.
I downloaded and rendered your image with your original settings. It took slightly over 3 min.
Then I dropped the sampling from 250 to 96 and added a noise threshold of 0.1. (changed from the default of 0.01.)
Doing just those two things cut my render time to a few ticks over 51 seconds.
For your purpose, you don’t need all of those samples. You are wasting computes. Increasing the noise threshold saves you even more. You are rendering video. (At 60 fps?!) By the time your video codec gets done compressing your footage, much of your quality goes down the toilet. Even at 24 fps., the human eye doesn’t have enough time to discriminate the difference, anyway.
If, further, you dropped your frame rate from 60 to 30, you’d save even more time in the number of frames you have to render for a given amount of screen time.
Cut your samples from 250 to 96.
Increase your noise threshold to 0.1.
Lower your frame rate from 60 to 30. (or even 24)
If you did just those three things without changing anything else, you would cut your render time from more than 48 hours to three or four and nobody who watched your video would even notice.
BTW: Change your image dimensions from 2440 px. X 1440 px. to either 2432 x 1440 or 2448 x 1440 and you’ll make things even more efficient.
(MPEG-4 codecs work best when your pixel dimensions are even multiples of 16.)
