←back to thread

Pixar's Render Farm

(twitter.com)
382 points brundolf | 3 comments | 02 Jan 21 19:56 UTC | HN request time: 0.477s | source
Show context
supernova87a ◴[02 Jan 21 21:05 UTC] No.25616522[source]▶
I would love to know about some curious questions, for example:

If there's a generally static scene with just characters walking through it, does the render take advantage of rendering the static parts for the whole scene once, and then overlay and recompute the small differences caused by the moving things in each individual sub frame?

Or, alternatively what "class" of optimizations does something like that fall into?

Is rendering of video games more similar to rendering for movies, or for VFX?

What are some of physics "cheats" that look good enough but massively reduce compute intensity?

What are some interesting scaling laws about compute intensity / time versus parameters that the film director may have to choose between? "Director X, you can have <x> but that means to fit in the budget, we can't do <y>"

Can anyone point to a nice introduction to some of the basic compute-relevant techniques that rendering uses? Thanks!

replies(5): >>25616535 #>>25616590 #>>25616686 #>>25617013 #>>25618032 #
dagmx ◴[02 Jan 21 21:13 UTC] No.25616590[source]▶
If you're interested in production rendering for films, there's a great deep dive into all the major studio renderers https://dl.acm.org/toc/tog/2018/37/3

As for your questions:

> Is rendering of video games more similar to rendering for movies, or VFX?

This question is possibly based on an incorrect assumption that feature (animated) films are rendered differently than VFX. They're identical in terms of most tech stacks including rendering and the process is largely similar overall.

Games aren't really similar to either since they're raster based rather than pathtraced. The new RTX setups are bringing those worlds closer. However older rendering setups like REYES that Pixar used up until Finding Dory, are more similar to games raster pipelines. though that's trivializing the differences.

A good intro to rendering is reading Raytracing in a Weekend (https://raytracing.github.io/books/RayTracingInOneWeekend.ht...), and Matt Pharr's PBRT book (http://www.pbr-book.org/)

replies(2): >>25616622 #>>25617396 #
1. supernova87a ◴[02 Jan 21 21:16 UTC] No.25616622[source]▶
Thanks!

(I was also reading the OP which says "...Our world works quite a bit differently than VFX in two ways..." hence my curiosity)

replies(2): >>25616698 #>>25616726 #
2. lattalayta ◴[02 Jan 21 21:26 UTC] No.25616698[source]▶
One way that animated feature films are different than VFX is schedules. Typically, an animated feature from Disney or Pixar will take 4-5 years from start to finish, and everything you see in the movie will need to be created and rendered from scratch.

VFX schedules are usually significantly more compressed, typically 6-12 months, so often times it is cheaper and faster to throw more compute power at a problem rather than paying a group of highly knowledgeable rendering engineers and technical artists to optimize it (although, VFX houses will still employ rendering engineers and technical artists that know about optimization). Pixar has a dedicated group of people called Lightspeed technical artists whose sole job is to optimize scenes so that they can be rendered and re-rendered faster.

Historically, Pixar is also notorious for not doing a lot of "post-work" to their rendered images (although they are slowly starting to embrace it on their most recent films). In other words, what you see on film is very close to what was produced by the renderer. In VFX, to save time, you often render different layers of the image separately and then composite them later in a software package like Nuke. Doing compositing later allows you to fix mistakes, or make adjustments in a faster way than completely re-rendering the entire frame.

3. dagmx ◴[02 Jan 21 21:29 UTC] No.25616726[source]▶
I suspect they mean more in approaches to renderfarm utilization and core stealing.

A lot of VFX studios use off the shelf farm management solutions that package up a job as a whole to a node.

I don't believe core stealing like they describe is unique to Pixar, but is also not common outside Pixar either, which is what they allude to afaik. It's less an animation vs VFX comparison, as just studio vs studio infrastructure comparison.