Pixar Uses Real Raytracing for First Time in Monster's University

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JCreasy

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I don't claim to be an expert on cg animation, but just based on what I've learned by following video games, I had alway assumed Pixar used raytracing to light their movies.

Turns out that's not true.

All their earlier films used hacks to get the results we've seen. Monster's University will be the first Pixar film to throughly implement ray tracing for their lighting.

Check out this interview with Chris Horne at Mason Smith's blog:

I was on MU from May 2012 until April 2013 -- so yeah I worked on it for a *very very* long time as far as the lighting department is concerned. When I joined it was only leads + 1 shot lighter and me. It was a blast to work on because we completely rewrote our lighting system to be a raytraced/GI system -- and since I was on early I got to test the boundaries of it and figure out how we should light the show from a technical aspect. We really explored the lighting system - and I feel like a significant amount of work we did back then is going to live on in the way we light shows with this new technology.
There's a huge difference in MU compared to past films. Even people that don't know anything about our tech change going in walk out going "HOLY CRAP!"....but they have a hard time putting their finger on why it looks so awesome. Personally I see a huge difference between MU and Brave - there's more shaping, more little splashes of color, and everything feels a little bit more dynamic and pulled together.
Historically we don't use raytracing. It wasn't until Cars that we actually supported raytracing (and even then it was a haphazard and mostly broken support). We really only used it for highly reflective smooth curved surfaces that absolutely needed to be truly reflected and not faked. We fake almost everything - mirrors, wet surfaces, eyes, shiny props like belt buckles/spoons/swords/etc. We obviously can't get away with that on Lightning McQueen - so we would cache out the scene into a brickmap (essentially a kd-tree with shading attached to the voxels) and fire rays against that (so even then....we aren't doing traditional raytracing).
So our Director of Photography went to a studio that is so clearly raytracing averse and essentially said "We're raytracing everything. True reflection and refraction in the eyes reflecting actual SCENE GEOMETRY and not a brickmap. Yep - we're refracting through the cornea onto the sclera and iris. Oh and all your shadows are raytraced now - no more shadowmaps.
I was really impressed with how MU looked in the trailers and now I know why.

More at the link.

http://thisanimatedlife.blogspot.ch/2013/05/pixars-chris-horne-sheds-new-light-on.html
 

magicstop

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We obviously can't get away with that on Lightning McQueen - so we would cache out the scene into a brickmap (essentially a kd-tree with shading attached to the voxels) and fire rays against that (so even then....we aren't doing traditional raytracing).
THE FUCK IS THIS?

Jargon aside, pretty damn cool. Neat to know that the light is all behaving, rather than being more or less drawn. I'd be interested in seeing comparable side by sides, though. Also makes my GPU hurt.
 

Randdalf

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THE FUCK IS THIS?

Jargon aside, pretty damn cool. Neat to know that the light is all behaving, rather than being more or less drawn. I'd be interested in seeing comparable side by sides, though. Also makes my GPU hurt.
They'd create a new version of the scene but it looked a bit like Minecraft (i.e. split up into blocks/bricks/voxels that sort of resembled the scene). They stored all the bricks in a data structure called a kd-tree, which essentially divides 3d space into two, recursively, like so:

https://upload.wikimedia.org/wikipedia/commons/thumb/b/bf/Kdtree_2d.svg/300px-Kdtree_2d.svg.png

They do this because it massively improves the performance of doing ray tracing against that scene.
 

magicstop

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They'd create a new version of the scene but it looked a bit like Minecraft (i.e. split up into blocks/bricks/voxels that sort of resembled the scene). They stored all the bricks in a data structure called a kd-tree, which essentially divides 3d space into two, recursively, like so:

https://upload.wikimedia.org/wikipedia/commons/thumb/b/bf/Kdtree_2d.svg/300px-Kdtree_2d.svg.png

They do this because it massively improves the performance of doing ray tracing against that scene.
I almost follow. At least, the Minecraft bit :D But the gist, I get. Thanks for explaining!
 

linkman26

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I refuse to see the movie based on the fact that Pete Doctor isn't directing it and it's not canon, completely missing the line from the first movie where Mike says that Sulley was jealous of his looks since the 4th grade.
 

Randdalf

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Does anyone know if Avatar used real raytracing?
Avatar was rendered using Pixar's RenderMan (http://renderman.pixar.com/view/movies-and-awards), so unless they added some other software on top or only used RenderMan in a limited capacity, possibly not. Note that Pixar did use ray tracing, just in a limited capacity, so it's not as if all these films are completely devoid of it, it was just unnecessary. So, this might actually have implications for the quality of CGI as a whole.
 

Mariolee

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I refuse to see the movie based on the fact that Pete Doctor isn't directing it and it's not canon, completely missing the line from the first movie where Mike says that Sulley was jealous of his looks since the 4th grade.
It's hard to believe they won't acknowledge this in the film since it's been brought up so much.
 

FoxSpirit

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Avatar was rendered using Pixar's RenderMan (http://renderman.pixar.com/view/movies-and-awards), so unless they added some other software on top or only used RenderMan in a limited capacity, possibly not. Note that Pixar did use ray tracing, just in a limited capacity, so it's not as if all these films are completely devoid of it, it was just unnecessary. So, this might actually have implications for the quality of CGI as a whole.
Yeah, I must say the whole scenes now REALLY gel together well. Pretty neat if you know what you are looking for.

Also, hopefully that means Avatar 2 CGI now looks actually good. Part 1 was creative but only okay.
 

mr stroke

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I have not seen the film yet so it could look amazing, but the trailers/screens don't look much different than Monsters Inc

 

Like the hat?

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Probably a dumb question, and I know these movies are made on huge farms and such, but if a single standard like $250 desktop gpu was (able to be) used, how long would it take to render a single frame of a movie like the first Toy Story?
 

JCreasy

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I have not seen the film yet so it could look amazing, but the trailers/screens don't look much different than Monsters Inc

I can definitely see the difference here. The colors really pop. Old school still looks pale, a little pastel even:



 

Akira

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Probably a dumb question, and I know these movies are made on huge farms and such, but if a single standard like $250 desktop gpu was (able to be) used, how long would it take to render a single frame of a movie like the first Toy Story?
A couple of months until it crashes due to running out of RAM.
 

Randdalf

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Probably a dumb question, and I know these movies are made on huge farms and such, but if a single standard like $250 desktop gpu was (able to be) used, how long would it take to render a single frame of a movie like the first Toy Story?
This video http://www.youtube.com/watch?v=ykiqWBUL8Lk

Suggests it wouldn't take that long at all, although the scenes are likely to be more complex with less fancy effects than he uses.
 

Nickiepoo

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Makes sense, raytracing is a monster.

Renderman has supported it fine for as long as I've used it but I think that was just after Cars came out so there we go.
 

jett

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I didn't even notice the difference in their trailers. In fact MU is probably one of Pixar's ugliest movies, if they're any indication.
 

-griffy-

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I have not seen the film yet so it could look amazing, but the trailers/screens don't look much different than Monsters Inc

It's not something that's going to be overtly obvious, but a subtle difference to the lighting. You can actually see some of it in this shot you posted. There is light bouncing off the brown/orange suitcase to his left that is causing a faint glow of orange to hit his lower body.

Compare that to the shots of the first Monster's Inc posted in this thread where you can clearly see they just have different lights set up to hit each object, but they are only affecting that object and not the environment. The light essentially "stops" when it hits an object.

That's the kind of stuff raytracing is doing, it's tracking not only the light hitting an object, but how the light bounces off that object onto the surrounding environment. It means you can get highly accurate or realistic lighting, reflections and shadows, though it significantly increases render time.
 

Log4Girlz

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It's not something that's going to be overtly obvious, but a subtle difference to the lighting. You can actually see some of it in this shot you posted. There is light bouncing off the brown/orange suitcase to his left that is causing a faint glow of orange to hit his lower body.

Compare that to the shots of the first Monster's Inc posted in this thread where you can clearly see they just have different lights set up to hit each object, but they are only affecting that object and not the environment. The light essentially "stops" when it hits an object.

That's the kind of stuff raytracing is doing, it's tracking not only the light hitting an object, but how the light bounces off that object onto the surrounding environment. It means you can get highly accurate or realistic lighting, reflections and shadows, though it significantly increases render time.
Yep, accurate, realistic lighting without having to put thought into how to fake the look you want. Its just done automatically.
 

BriareosGAF

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You can't ray trace the soul back into their writing, though. The real question is--who will be the next Pixar?
 

XiaNaphryz

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Avatar was rendered using Pixar's RenderMan (http://renderman.pixar.com/view/movies-and-awards), so unless they added some other software on top or only used RenderMan in a limited capacity
Pixar didn't use PRman to its potential, IIRC. For example ILM has primarily been a Renderman shop as well since they could always get to use it due to the Lucasfilm sale of Pixar, and often was the main group pushing the software in several ways. ILM would still try to find ways to avoid using raytracing though, since its so time-consuming. They've found plenty of tricks to get similar quality to raytracing without resorting to it.

I'm salivating thinking about the cg software well be using in the next decade
This particular news isn't really that noteworthy in terms of pushing tech, they just decided to finally sit down and optimize things in-house. Pretty sure stuff like "True reflection and refraction in the eyes reflecting actual SCENE GEOMETRY and not a brickmap" was first done for Davy Jones (at least partially anyway for refractions) and has since been done for stuff like Rango:



Also, Hulk in Avengers:

https://www.youtube.com/watch?v=MnQLjZSX7xM&hd=1#t=0m52s

But yeah, I wouldn't be surprised if someone's going to get past uncanny valley within that timeframe. ILM being under Disney's umbrella will also make it easier for Pixar and ILM to talk/work to each other also.
 

Log4Girlz

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Pixar didn't use PRman to its potential, IIRC. For example ILM has primarily been a Renderman shop as well since they could always get to use it due to the Lucasfilm sale of Pixar, and often was the main group pushing the software in several ways. ILM would still try to find ways to avoid using raytracing though, since its so time-consuming. They've found plenty of tricks to get similar quality to raytracing without resorting to it.



This particular news isn't really that noteworthy in terms of pushing tech, they just decided to finally sit down and optimize things in-house. Pretty sure stuff like "True reflection and refraction in the eyes reflecting actual SCENE GEOMETRY and not a brickmap" was first done for Davy Jones (at least partially anyway for refractions) and has since been done for stuff like Rango:



Also, Hulk in Avengers:

https://www.youtube.com/watch?v=MnQLjZSX7xM&hd=1#t=0m52s

But yeah, I wouldn't be surprised if someone's going to get past uncanny valley within that timeframe. ILM being under Disney's umbrella will also make it easier for Pixar and ILM to talk/work to each other also.
If you told me that Rango was raytraced I would have believed you without question.
 

cameron

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I guess I thought raytracing would be... Laser rays, used to capture performances?

So this is less interesting, but way better news (probably? Laser ray mocap sounds pretty cool...).
From what Pixar has revealed publicly in the past, they don't seem to have a strong interest in motion capture for the types of animated films they produce.
 

JCreasy

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Pixar didn't use PRman to its potential, IIRC. For example ILM has primarily been a Renderman shop as well since they could always get to use it due to the Lucasfilm sale of Pixar, and often was the main group pushing the software in several ways. ILM would still try to find ways to avoid using raytracing though, since its so time-consuming. They've found plenty of tricks to get similar quality to raytracing without resorting to it.



This particular news isn't really that noteworthy in terms of pushing tech, they just decided to finally sit down and optimize things in-house. Pretty sure stuff like "True reflection and refraction in the eyes reflecting actual SCENE GEOMETRY and not a brickmap" was first done for Davy Jones (at least partially anyway for refractions) and has since been done for stuff like Rango:



Also, Hulk in Avengers:

https://www.youtube.com/watch?v=MnQLjZSX7xM&hd=1#t=0m52s

But yeah, I wouldn't be surprised if someone's going to get past uncanny valley within that timeframe. ILM being under Disney's umbrella will also make it easier for Pixar and ILM to talk/work to each other also.
Wow thanks for the info!

This explains why Davy Jones and Rango resonated with me. The hulk too. I could never put my finger on it but the textures (shaders?) felt nearly photo-real to me. I knew lighting had something to do with it.

Also, as far as MU's use of more complex tech, this shot from the trailer resonated with me when I first saw it:



It felt warm in ways I've never seen in a Pixar film. Now I know why.
 

Log4Girlz

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Wow thanks for the info!

This explains why Davy Jones and Rango resonated with me. The hulk too. I could never put my finger on it but the textures (shaders?) felt nearly photo-real to me. I knew lighting had something to do with it.

Also, as far as MU's use of more complex tech, this shot from the trailer resonated with me when I first saw it:



It felt warm in ways I've never seen in a Pixar film. Now I know why.
I wish they would have a design a little more sophisticated than a booger with arms and legs.
 

Demon Ice

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Well that would explain why I didn't realize the MU trailer was CGI until I saw the first actual monster.
 

agrajag

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Holy shit, if that thing wasn't obviously a fantastical creature, I'd say it looks photo realistic. The back lighting on the fur is incredible.
 

Shin Johnpv

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Pixar didn't use PRman to its potential, IIRC. For example ILM has primarily been a Renderman shop as well since they could always get to use it due to the Lucasfilm sale of Pixar, and often was the main group pushing the software in several ways. ILM would still try to find ways to avoid using raytracing though, since its so time-consuming. They've found plenty of tricks to get similar quality to raytracing without resorting to it.



This particular news isn't really that noteworthy in terms of pushing tech, they just decided to finally sit down and optimize things in-house. Pretty sure stuff like "True reflection and refraction in the eyes reflecting actual SCENE GEOMETRY and not a brickmap" was first done for Davy Jones (at least partially anyway for refractions) and has since been done for stuff like Rango:



Also, Hulk in Avengers:

https://www.youtube.com/watch?v=MnQLjZSX7xM&hd=1#t=0m52s

But yeah, I wouldn't be surprised if someone's going to get past uncanny valley within that timeframe. ILM being under Disney's umbrella will also make it easier for Pixar and ILM to talk/work to each other also.
For non-renderman rendered stuff, I believe all of Blue Sky's movies feature true raytracing as well. I remember being at a talk by one of their texture artists that talked about it. I'm trying to remember the exact details but the talk was from 2006/2007. The main thing I remember getting from it was that their proprietary renderer was focused on raytracing, recreating how real light worked, and they were big on just using lights from their actual sources. IE If the only light source in a shot is a campfire that's the only light in the scene and no faked bounce lights and such. At the time I do believe he said they try to do as little compositing as well, and try to get it all there in 1 render.
 

XiaNaphryz

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I'm pretty confident Abrams patented all future lens flares for Star Trek movies.

I like the idea of using ray tracing. Advances in technology put to good use in the entertainment industry.
Again, using ray tracing for lighting has been done by visual effects studios since the late 90s since they need more realistic lighting solutions for live action work. Pixar's just finally deciding to also go with that route, if anything everyone using PRman would likely benefit from any improvements Pixar has made to the renderer.
 
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