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Pixar's Chris Horne Sheds New Light on Monsters University

thisanimatedlife.blogspot.com

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Re: Pixar's Chris Horne Sheds New Light on Monsters University

#111

Post by berkut »

splt wrote: post #78
berkut wrote: post #61

Earlier quoted context omitted.

Yes, because the article (and the person in it) doesn't seem to understand the difference between path tracing (ray tracing with global illumination - multiple bounces even with diffuse surfaces), and ray tracing = sending rays around a scene and bouncing them off specular reflective/refractive surfaces - which Pixar have been doing for years. It's been possible to write raytraced shaders in PRMan for over 12 years n…

Cars was in production about 10-12 years ago. Maybe you're thinking Cars 2?

No, the guy in the article was wrong - it's been possible to do in PRMan since at least 2000, but it was very slow (they didn't have any decent acceleration structures for the ray intersection), so it generally wasn't used that much. But it was possible.

For PRMan 13 (which Pixar used for Cars in 2006), they added semi-decent acceleration structures which sped up raytracing a bit. But you still had to use custom shaders to cast rays.

With PRMan 17, ray tracing is now a first-class citizen in PRMan, and it can also trace rays from the camera instead of doing the traditional (pre 17) REYES rasterization of the surface and then shading that surface for reflection based on ray tracing.

Re: Pixar's Chris Horne Sheds New Light on Monsters University

#112

Post by Cthulhu_ »

primigenus wrote: post #90
jarrett wrote: post #31

For a bit of background: The article talks a lot about global illumination. Here's what that means. First, you have to understand the cheaper alternative, which is called local illumination. With local illumination, for each pixel, you figure out what object you're looking at, and where on that object. You take into account the normal (direction of the surface at that point) and the optical properties of the object a…

I wonder what would happen if you offloaded the rendering of a movie like Monsters University to something like Google Compute Engine. Would it cost an arm and a leg? Or would it solve a lot of scaling/cost/time challenges?

I actually wonder if Google, Amazon etc have enough idling servers to suddenly handle rendering a 90 minute movie (at approx. 11.5 hours / frame, if not more with these new lighting technologies).

Re: Pixar's Chris Horne Sheds New Light on Monsters University

#113

Post by Cthulhu_ »

baby wrote: post #63
mratzloff wrote: post #57

I was wondering what Toy Story would look like if they re-rendered it with today's technology. Well, it turns out they already did! It was part of the theatrical re-releases of Toy Story and Toy Story 2 in 3D. http://www.bigscreenanimation.com/2008/09/toy-story-re-relea... Were these re-rendered versions released in 2D on Blu-ray?

I wonder if you really see a difference.

Well, unless they changed the sources (models, lighting etc), probably not, however, re-rending would allow for higher resolution (1080P or cinema resolutions) and higher frame rates (not sure what blu-ray does in terms of frames), as well as tiny adjustments for display on modern cinema screens and TV's.

Re: Pixar's Chris Horne Sheds New Light on Monsters University

#114

Post by berkut »

craigc wrote: post #104
hayksaakian wrote: post #70

Earlier quoted context omitted.

based on the two numbers: 170 years and 11.5 hours, that means 129581.580089 tasks in parallel over 11.5 hours

I don't know for sure, but I would kind of doubt they are rendering all 130,000 frames in parallel. I would think it is more likely that when a scene is done and ready then that scene would be rendered and completed. There are a lot of other things going into each scene other than just the rendering (storyboarding, animating, lighting, etc) so it would be silly to wait for the entire film to be done and then render a…

Other than grading, compositing and sound, rendering's generally the final step - definitely, the modelling, lighting, animation and texturing have to be done before the rendering can be started.

Re: Pixar's Chris Horne Sheds New Light on Monsters University

#116

Post by davvid »

aaronbrethorst wrote: post #7

I was surprised that ray tracing in Pixar was historically a clunky, haphazard process. I always thought of it as this smooth, polished machine like something you would see at an Apple store. Life inside the sausage factory never quite looks like what outsiders would expect.

Most people probably think that Pixar uses Apple computers (e.g. the Apple references in Wall-E). In fact, Pixar is a Linux shop.

Re: Pixar's Chris Horne Sheds New Light on Monsters University

#117

Post by yardie »

KaiserPro wrote: post #23
aaronbrethorst wrote: post #7

I was surprised that ray tracing in Pixar was historically a clunky, haphazard process. I always thought of it as this smooth, polished machine like something you would see at an Apple store. Life inside the sausage factory never quite looks like what outsiders would expect.

A lot of the tools in pixar are wonderfully clunky. They went through a phase of hiring hip young things fresh out of MIT to write tools. Instead of nice friendly tools that play well together, they got a lot of domain specific languages.

It's been this way in the visual effects industry for decades. Most of the tools are used through a Posix layer with Perl to keep things tidy. Going into the VFX forums even a few years ago I was amazed at illustrators knowing enough Perl and Python to get the job done, because, "Designers can't code good!"

Even the commercial stuff looks like some graduate students thesis work. A basic Java GUI and about 50+ commandline arguments.

Re: Pixar's Chris Horne Sheds New Light on Monsters University

#118

Post by mprovost »

munificent wrote: post #58
aidenn0 wrote: post #49

Earlier quoted context omitted.

They must do them heavily in parallel then; otherwise it would take 170 years to render the movie.

Haha, yes, yes they do. You can see a few pictures of Pixar's render farm in [1]. According to [2] (which is where that 11.5 hours comes from) for Cars 2, they had 12,500 CPU cores for rendering. [1] http://www.slashfilm.com/cool-stuff-a-look-at-pixar-and-luca... [2] http://jalopnik.com/5813587/12500-cpu-cores-were-required-to...

Just for comparison Weta Digital had 35,000 cores for rendering Avatar.

Re: Pixar's Chris Horne Sheds New Light on Monsters University

#119

Post by MagerValp »

primigenus wrote: post #90
jarrett wrote: post #31

For a bit of background: The article talks a lot about global illumination. Here's what that means. First, you have to understand the cheaper alternative, which is called local illumination. With local illumination, for each pixel, you figure out what object you're looking at, and where on that object. You take into account the normal (direction of the surface at that point) and the optical properties of the object a…

I wonder what would happen if you offloaded the rendering of a movie like Monsters University to something like Google Compute Engine. Would it cost an arm and a leg? Or would it solve a lot of scaling/cost/time challenges?

This came up in a discussion I had with a tech at Disney Animation. The biggest issue is actually getting the assets from the workstation over to the rendering farm. Since the assets for a single scene can be many gigabytes using someone else's far away render farm would be prohibitively slow.

Re: Pixar's Chris Horne Sheds New Light on Monsters University

#120

Post by talmand »

kibibu wrote: post #84
jarrett wrote: post #31

For a bit of background: The article talks a lot about global illumination. Here's what that means. First, you have to understand the cheaper alternative, which is called local illumination. With local illumination, for each pixel, you figure out what object you're looking at, and where on that object. You take into account the normal (direction of the surface at that point) and the optical properties of the object a…

I appreciate the clear description of local vs global illumination. This isn't quite what the article is discussing though. Pixar have had a global illumination system in place at least since Up , and maybe earlier [1]. However, it was one that integrated with their rasterizer. The article is now claiming that Pixar have switched to Raytracing exclusively, which really is actually a HUGE change, as Renderman only int…

Wait a sec, I thought that customers were asking for ray tracing in RenderMan before then and they used the first Cars as a testbed for those capabilities.
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