4 ms·

I was randomly curious how long it would take to render a full movie at the quality of that forest image, which absolutely blew my mind. At 24fps, a 2h movie h

I was randomly curious how long it would take to render a full movie at the quality of that forest image, which absolutely blew my mind. At 24fps, a 2h movie has 172800 frames. 21,970,310 M1 seconds or 8.5 M1 months. Which is less than I was expecting. The rendering seems to scale linearly per core too. Presumably bad math or a lot more rendering complexity for the pixar super computer deploys?

convery 5y ago
Worth keeping in mind is the similarity of frames. Or, the lack of difference. If you know that the light-source isn't changing then you can get way with just copying the last frame and super-imposing < 300 pixels to reflect what's changed. i.e. there's no need to render the same wall for every frame.
- bhouston 5y ago
  Nobody does that though. But you can denoise a sequence which is similar.
  - bonestamp2 5y ago
    I'm guessing they don't interpolate frames either, but maybe that would be a good time saving feature if you know the end compression format and you can just interpolate the frames at the render stage instead of re-encoding it again later.
    - bhouston 5y ago
      There are ai upscalers and also ai interpolators to uprez the frame rate. Haven’t heard they used used in film but I suspect they will be as they get better.
- judge2020 5y ago
  If you're using the same software, you can assume there's no super high-level speedups like that happening on the M1, although it might specifically target speedups on common instructions used in these workloads.
dagmx 5y ago
You've got a few flawed basis points in your math. 1) that forest isn't near the complexity of most major feature films. It's great, but it's got a ton of instancing, it's not got very complex shaders, it's not got very complex lighting. It's a good benchmark scene, but it's not approaching the level of scenes in most feature films. 2) You're assuming a single render happens per frame. Every scene in a movie is rendered several times. Potentially every single time a new hand touches it, and definitely multiple times as lighters iterate on it. On average I think a single shot must be rendered about 40-50 times or more in a large production. At least 10 times per each major department. 3) Pixar and other studios don't have really extraordinary computers. They're usually run of the mill HP or Dell workstation specced machines with a dual Xeon and tons of RAM. 4) static scenes with diffuse lighting are fast to render. Add in motion and things get tricky. Do you want motion blur in render (as opposed to composited in via motion vectors)? Well now you're sampling multiple frames. What about depth of field? Way more samples to resolve properly. Now add in more lights, and you need more samples per light to resolve a noiseless render.
- pineconebutt 5y ago
  > Pixar and other studios don't have really extraordinary computers. They're usually run of the mill HP or Dell workstation specced machines with a dual Xeon and tons of RAM. "Pixar has a huge 'render farm,' which is basically a supercomputer composed of 2000 machines, and 24,000 cores. This makes it one of the 25 largest supercomputers in the world." Source: https://sciencebehindpixar.org/pipeline/rendering https://sciencebehindpixar.org/pipeline/rendering
- berkut 5y ago
  1. Instancing doesn't reduce the complexity of rendering a scene in terms of light transport, it only reduces the memory storage and Accel structure complexity. Actually, a forest with occluding foliage geometry is a quite difficult light transport situation: it's very difficult for next event estimation to work efficiently, so therefore most of the lighting is indirect and therefore is quite noisy, as it's difficult to find the environment / IBL light for the sun. Portal guiding and NEE guiding can help a bit, but it can still be quite slow.
hajile 5y ago
Modern animated films often use 150,000 CPU cores over 1-2 years to render everything.

convery 5y ago

Worth keeping in mind is the similarity of frames. Or, the lack of difference. If you know that the light-source isn't changing then you can get way with just copying the last frame and super-imposing < 300 pixels to reflect what's changed. i.e. there's no need to render the same wall for every frame.

bhouston 5y ago
Nobody does that though. But you can denoise a sequence which is similar.
- bonestamp2 5y ago
  I'm guessing they don't interpolate frames either, but maybe that would be a good time saving feature if you know the end compression format and you can just interpolate the frames at the render stage instead of re-encoding it again later.
  - bhouston 5y ago
    There are ai upscalers and also ai interpolators to uprez the frame rate. Haven’t heard they used used in film but I suspect they will be as they get better.
judge2020 5y ago
If you're using the same software, you can assume there's no super high-level speedups like that happening on the M1, although it might specifically target speedups on common instructions used in these workloads.

dagmx 5y ago

You've got a few flawed basis points in your math. 1) that forest isn't near the complexity of most major feature films. It's great, but it's got a ton of instancing, it's not got very complex shaders, it's not got very complex lighting. It's a good benchmark scene, but it's not approaching the level of scenes in most feature films. 2) You're assuming a single render happens per frame. Every scene in a movie is rendered several times. Potentially every single time a new hand touches it, and definitely multiple times as lighters iterate on it. On average I think a single shot must be rendered about 40-50 times or more in a large production. At least 10 times per each major department. 3) Pixar and other studios don't have really extraordinary computers. They're usually run of the mill HP or Dell workstation specced machines with a dual Xeon and tons of RAM. 4) static scenes with diffuse lighting are fast to render. Add in motion and things get tricky. Do you want motion blur in render (as opposed to composited in via motion vectors)? Well now you're sampling multiple frames. What about depth of field? Way more samples to resolve properly. Now add in more lights, and you need more samples per light to resolve a noiseless render.

pineconebutt 5y ago
> Pixar and other studios don't have really extraordinary computers. They're usually run of the mill HP or Dell workstation specced machines with a dual Xeon and tons of RAM. "Pixar has a huge 'render farm,' which is basically a supercomputer composed of 2000 machines, and 24,000 cores. This makes it one of the 25 largest supercomputers in the world." Source: https://sciencebehindpixar.org/pipeline/rendering https://sciencebehindpixar.org/pipeline/rendering
berkut 5y ago
1. Instancing doesn't reduce the complexity of rendering a scene in terms of light transport, it only reduces the memory storage and Accel structure complexity. Actually, a forest with occluding foliage geometry is a quite difficult light transport situation: it's very difficult for next event estimation to work efficiently, so therefore most of the lighting is indirect and therefore is quite noisy, as it's difficult to find the environment / IBL light for the sun. Portal guiding and NEE guiding can help a bit, but it can still be quite slow.

hajile 5y ago

Modern animated films often use 150,000 CPU cores over 1-2 years to render everything.