Animation render time

[Salmaasa]

Hello,
I am trying my first animation project. It's a simple interior camera movement project. Total frames are 480 and the resolution is 1920*1080 and noise level set to 4%. I am confused about the render time per frame. It took me about 1 hour to render the first frame. It seemed unrealistic. I saved the uhd cache beforehand. I am wondering if this is normal or I have done something wrong. Can someone suggest me how I can reduce the render time?
Thanks in advance!

My pc configuration: i7 11700 8C/16T, Ram 32GB

[TomG]

We can't tell if that is expected or not without knowing something about the scene to see how complex it is, at very least a look at the rendered image would help, but it might even take a look at the scene to see if something is set up wrong. That said, it is not that fast a processor (https://corona-renderer.com/benchmark/results/cpu/11700/3 ) too, so longer render times might be expected (my 3960X would be about three times faster, so maybe around 20 minutes per frame, which to me does not sound unreasonable... without seeing the render, at least :) )

Also, are you sure you aren't running out of RAM? How much is Corona using when rendering? No low RAM warning message?

[Salmaasa]

We can't tell if that is expected or not without knowing something about the scene to see how complex it is, at very least a look at the rendered image would help, but it might even take a look at the scene to see if something is set up wrong. That said, it is not that fast a processor (https://corona-renderer.com/benchmark/results/cpu/11700/3 ) too, so longer render times might be expected (my 3960X would be about three times faster, so maybe around 20 minutes per frame, which to me does not sound unreasonable... without seeing the render, at least :) )

Also, are you sure you aren't running out of RAM? How much is Corona using when rendering? No low RAM warning message?

Here is a video and render of the scene. Yes, I sometimes get a low ram warning. I have been thinking of upgrading the ram to 64. I am just not sure yet if it's worth it. What do you suggest?
Thank you for replying.

[TomG]

To that quality, at full 4K, on that processor, I'd say an hour per frame is pretty good going :) That said, if you ever get a low RAM warning, then Corona's rendering speed will be severely crippled, so you want to avoid that - less render elements, smaller resolution, are probably the keys here to ensuring things fit within memory.

[Salmaasa]

To that quality, at full 4K, on that processor, I'd say an hour per frame is pretty good going :) That said, if you ever get a low RAM warning, then Corona's rendering speed will be severely crippled, so you want to avoid that - less render elements, smaller resolution, are probably the keys here to ensuring things fit within memory.

To render in 4k, it takes 4-5 hours. I am rendering the video at 1920*1080p. I will try what you suggested. Thank you so much for helping!

[romullus]

If single frame in 4K takes about 4 hours to render, it's only natural to assume that the same frame in full HD will take 1 hour, since it has 4 times less pixels. Upgrading RAM will not help in the slightest if your system is not actually running out of RAM. Corona low memory warning is just that - a warning, it does not necessary means that Corona needs to use swap. If that would be the case, then your render probably would take 40 hours and more and you would see 100% disk usage and pretty low CPU usage.

As Tom already mentioned, your CPU is not very fast and 4 hours for 4K interior doesn't sound unreasonable. That being said, it's quite possible that your scene can be tweaked further to improve render times. Check the performance stats tab in the VFB, see if you have UHD/4K cache too low, or if rays/sample is excessively high. Maybe your background isn't set right, perhaps window glass blocks too much light, or maybe your albedo is too high. Maybe your materials could be simplified to save some time. Also consider rendering shorter and cleaning remaining noise with denoiser. In summary, do some scene inspection and try to find ways to improve render time - when rendering animation, every saved second counts.

[Salmaasa]

If single frame in 4K takes about 4 hours to render, it's only natural to assume that the same frame in full HD will take 1 hour, since it has 4 times less pixels. Upgrading RAM will not help in the slightest if your system is not actually running out of RAM. Corona low memory warning is just that - a warning, it does not necessary means that Corona needs to use swap. If that would be the case, then your render probably would take 40 hours and more and you would see 100% disk usage and pretty low CPU usage.

As Tom already mentioned, your CPU is not very fast and 4 hours for 4K interior doesn't sound unreasonable. That being said, it's quite possible that your scene can be tweaked further to improve render times. Check the performance stats tab in the VFB, see if you have UHD/4K cache too low, or if rays/sample is excessively high. Maybe your background isn't set right, perhaps window glass blocks too much light, or maybe your albedo is too high. Maybe your materials could be simplified to save some time. Also consider rendering shorter and cleaning remaining noise with denoiser. In summary, do some scene inspection and try to find ways to improve render time - when rendering animation, every saved second counts.

Thank you so much. I learned a lot from your reply. Here's a snip from the stats tab. I can't quite catch what is the limit of low cache or high rays/sample. Can you help me?

[romullus]

Both stats looks good. Generally you would want that cache success rate would be at least 50% As for the rays/sample - 40 is perfectly acceptable for interior, it shows that in your scene is no overly complicated materials, too much AO, or too high albedo. Other stats are also looking normal. It could be that your scene is already pretty much well optimized and there's not much you can do, except to render it on faster computer, or use services of render farms.

[Salmaasa]

Both stats looks good. Generally you would want that cache success rate would be at least 50% As for the rays/sample - 40 is perfectly acceptable for interior, it shows that in your scene is no overly complicated materials, too much AO, or too high albedo. Other stats are also looking normal. It could be that your scene is already pretty much well optimized and there's not much you can do, except to render it on faster computer, or use services of render farms.

Thank you! I will try that.