10 ms·
Mathematicians bring ocean to life for Disney's 'Moana'
- avenoir 10y agoI was looking at the animation referenced in the article of water flowing over a rocky terrain and couldn't help but notice almost life-like and pixel-perfect precision of collision detection between water particles and the rocky surface. Yet, in modern gaming, while it's improved a great deal, quite often you'll see surfaces "fusing" together before a collision is detected. I think there is a more technical term for this, but it's not coming to mind. Is this just a matter of usability vs performance?
- bookmarkacc 10y agoI would imagine its a performance issue. For Moana they can render the water on a server farm with has much computing power as they need. Where a console or personal computer is quite limited in contrast.
- sam152 10y agoFurther to that point they can take as long as they like to render a single frame.
- SomeStupidPoint 10y agoThe movie is using a whole compute cluster to do a physics simulation when rendering the movie. Your computer has 1 CPU and 1 GPU. Your computer is just very limited in how much attention to detail it can have, because it has wildly less processing power and has to get its job done in real time. By contrast, Disney is using a server farm to spend 3 seconds analyzing the mechanics of a tuft of hair wiggling in the breeze for 1 second.
- tarr11 10y agoHas anyone tried to make a real game in the same way? Ie a game which was hosted on a remote desktop that had direct access to a GPU server farm on a very fast network.
- aidos 10y agoNot a field I work in but I guess it would never work. You'll have the network latency to contend with. Or people would need to self host a server farm, which probably makes your market pretty small :-)
- TeMPOraL 10y agoI wouldn't say never. The golden rule of computer games code is that you get to cheat a lot.
- icebraining 10y agohttps://www.playstation.com/en-us/explore/playstationnow/ https://www.playstation.com/en-us/explore/playstationnow/
- AJ007 10y agoIt certainly could happen - http://www.nvidia.com/object/cloud-gaming.html http://www.nvidia.com/object/cloud-gaming.html - how much will someone pay per hour to play one game? It feels like a timewarp to pre-AOL when online games cost more per hour than minimum wage.
- styrophone 10y agohttp://www.nvidia.com/object/cloud-gaming.html http://www.nvidia.com/object/cloud-gaming.html
- danielmorozoff 10y agoThis was initially attempted by G-Cluster in 2000, Crytek tried it as well, popularized by OnLive (who started working on it in 2003) and blew up in 2010. The general term for it is cloud gaming https://en.wikipedia.org/wiki/Cloud_gaming https://en.wikipedia.org/wiki/Cloud_gaming
- AJ007 10y agoAdditionally, multiplayer games often have to run a low-geometry simulation server side to reduce cheating and account for prediction/latency sync issues. While certainly not directly linked to poor physics simulations of water in computer games I would guess it has played a big role in holding back advancements in this area because how much locally-only non-game mechanic influencing visuals could cause contrast with need to be duplicated on the server physics.
- amptorn 10y agoThe other thing to remember is that Disney are completely at liberty to reject and re-render scenes when something doesn't look perfect. Arguably, this even applies to examples chosen for the demo video.
- JonnieCache 10y agoTo put this in perspective, 60fps == ~16.7ms per frame. That's 16.7ms to run your WHOLE game engine, you get some fraction of that left over to do rendering.
- remir 10y agoThe thing I noticed was how there seems to be some sort of hydrophobic coating on the rocks. They don't get wet like real rocks. The lava demo is similar.
- Lanzaa 10y agoThe quality of game renderings will lag behind movie renderings for a long time. At 60fps there is about 16.7ms available to render each frame. For a movie[1]: > There's a principle I call The Law of Constancy of Pain. Back when we made The Adventures of André & Wally B. in 1983 a typical frame took from several minutes to a few hours to compute. Now computers are literally millions of times more powerful and a typical final render takes from a few minutes to a few hours to compute, averaging somewhere between 2 and 4 hours. Render times have remained flat for over 30 years because that's just how long people are willing to wait for them. So movie artists are willing to have each frame of a movie take 2-4 hours to render vs 16.7 milliseconds. [1]: https://www.quora.com/How-long-does-it-take-to-render-a-Pixar-film https://www.quora.com/How-long-does-it-take-to-render-a-Pixa...
- aidos 10y agoWe watched Monana a couple of weeks ago and afterwards my wife said that she was amazed with how good the water looked. I said, I bet there were a bunch of mathematicians working on that :-) In another life I'd be doing maths for 3D movies. I went to university in Wellington where Weta are based (Peter Jackson's film companies) and at one point had a look around the digital arm. I seem to recall that they had the SGI machines as desktops and a big unix rendering farm. I just love the way you can use maths to create such magic. Anyway, if you haven't seen it yet, Moana is fantastic. Incredible animation, catchy pop hooks in the music and a brilliant storyline. It's wonderful to see a Disney film with a strong female lead that needs neither male support nor a love interest.
- raverbashing 10y ago> I seem to recall that they had the SGI machines as desktops and a big unix rendering farm. Is this during LoTR or even before? I though SGI was out by the time of LoTR
- deadlyllama 10y agoI'd guess before, they've been in the CGI business for quite a while. I saw a presentation from Milton back in 2000 (I'm also a VUW CS grad) with pictures of the render wall. At one point they bought the building of an ice cream factory in Miramar because it already had a massive electrical feed. They employ a fair few people in Wellington, my neighbour used to work for Weta as a sysadmin. Everyone was a contractor, doing 10 hour days. Not my scene.
- aidos 10y agoErm, not sure - it would have been 1999 maybe. I can't even remember what I was doing there, meeting a friend of a friend I think. Actually, I seem to recall that there were guys around at the time that were making the monsters for Xena or one of those shows.
- rodgerd 10y agoPretty sure Irix was the _Heavenly Creatures_ era.
- chis 10y agoThis is really cool. I wonder how one goes about getting into work like this - niche field but few qualified to work it, I'd guess.
- shas3 10y agoThe answer is right there in the article. Applied and numerical mathematicians at UCLA math department have for many years been helping out Hollywood with these problems. I'm sure their students, collaborators in other universities, etc. the academic community provides a gateway to get into this kind of work.
- danielmorozoff 10y agoThat said, UCLA Math dept is one of the best in the country. Some very talented people work there.
- anjc 10y agoStart with a PhD in a relevant area.
- raj_m 10y agoI am a Phd student in physics based simulation for Computer Graphics. I was a summer intern at WDAS and most of my colleagues were two of the following : 1) MS in CS with specialization in COmputer Graphics from places like UPenn 2) Phd in CS with specialization in Computer Graphics/Phd in Applied Mathematics from UCLA/Harvard.
- batty 10y agoYou can come do a PhD with me at Waterloo. #shamelessplug https://cs.uwaterloo.ca/~c2batty/ https://cs.uwaterloo.ca/~c2batty/
- chis 10y agoSmall world! I actually am majoring in comp sci and physics. I'll definitely message you if I end up getting into research next year.
- baq 10y agofor the EU viewers that are confused: in some countries the title and the character's name is Vaiana.
- NiceGuy_Ty 10y agoAlso coming into play during Moana is the hyperion rendering engine, which was first showcased in Big Hero 6: https://www.disneyanimation.com/technology/innovations/hyperion https://www.disneyanimation.com/technology/innovations/hyper... Also, here's an article containing some stills from the movie: http://blog.yiningkarlli.com/2016/11/moana.html http://blog.yiningkarlli.com/2016/11/moana.html
- joering2 10y agoThank for sharing - never been on DA website. The whole blog of publications is super interesting! https://www.disneyanimation.com/technology/publications https://www.disneyanimation.com/technology/publications
- JustinGarrison 10y agoGlad you like it. I work at Disney Animation. I have been pushing to get more "Innovations" posted but it's not always the easiest thing to get "secret sauce" published. https://www.disneyanimation.com/technology/innovations https://www.disneyanimation.com/technology/innovations I also helped push this forward to get other divisions to think about open sourcing code more often. http://disney.github.io/ http://disney.github.io/
- Animats 10y ago"Solve, or nearly solve, partial differential equations". That's game physics. Most of the effort is to come up with ways to "nearly solve" without having awful stuff happen. There's a long history of awful stuff, going back to when Seamus Blackley botched Trespasser in 1998. Game physics still tends to go "boink", because with impulse/constraint collisions, everything, including large, heavy objects, bounces instantaneously. Stuff flying apart, though, is rare now; most systems drain the energy out of a system when they detect that happening. It's physically wrong, but looks less awful. I used to work on this stuff. I solved the "boink" problem for articulated rigid body physics in the 1990s, but couldn't make it work in real time on 100MHz CPUs.
- ionwake 10y agoI loved the physics in Trespasser. Good times.
- santaclaus 10y ago> Stuff flying apart, though, is rare now; most systems drain the energy out of a system when they detect that happening. It's physically wrong, but looks less awful. Most games are using position based dynamics now (see Nvidia PhysX) so there isn't even a variational principle to arrive at the system from an energy. Just a constraint satisfaction problem with a weak notion of momentum coupled in.
- ufo 10y agoI wish the article went more into detail about what is novel about the algorithms they worked on.
- chestervonwinch 10y agohttps://www.math.ucla.edu/~jteran/papers/JSSTS15.pdf https://www.math.ucla.edu/~jteran/papers/JSSTS15.pdf
- bssrdf 10y agoYou can even play with the algorithm they used "The Affine Particle-In-Cell Method" using the code discussed here https://news.ycombinator.com/item?id=13325190 https://news.ycombinator.com/item?id=13325190
- supergirl 10y ago"where they used science to animate snow scenes" Cringes
- Fricken 10y agoI've been waiting decades to play a surf sim that utilizes proper fluid dynamics. Maybe before I die it'll happen.
- amelius 10y agoThis is nice from an artistic perspective. But from a computational physics perspective, it feels like cheating. How much of this is realistic? And are we now encouraging more and more people to focus on "fake" physics because it makes it somehow easier to produce something cool? I sure hope not.
- deburo 10y agoIt's not all about looking cool, it's about coming up with algorithms that are computable in a reasonable amount of time while also behaving as similarly as it is possible to interactions of objects in the real world. Faking physics is a mastery. Trade-offs are unavoidable.
- LeoPanthera 10y agoA little off-topic, but this site's cert appears to have a revoked intermediate authority. Pic: http://i.imgur.com/lIseT66.png http://i.imgur.com/lIseT66.png But no-one else seems to be complaining about this so I wonder if it's just me?
- Raticide 10y agoAll fine for me in Safari on OSX 10.10.3 http://i.imgur.com/ZwbQ08N.png http://i.imgur.com/ZwbQ08N.png
- santaclaus 10y agoThe hair was also great in Moana. It is fun to see nonlinear Cosserst rod theory in use on the big screen!
- megablast 10y agoScarily realistic: https://www.youtube.com/watch?v=3mULoRzfFcE https://www.youtube.com/watch?v=3mULoRzfFcE
- jordache 10y agoWhy is it that we can accept expressive/cartoonish looking characters but need to have the most realistic environmental rendering (light, physics effects)? I challenge the studios to be imaginative and equally expressive on the latter. Give us the miyazaki equivalent in 3d animated films. Don't take fthe easy way out by emulating reality. Put true art into it
- alxndr 10y agoMy guess is the uncanny valley[0] is still too big for "realistic" human characters. As for the goofy-looking chicken, it's convenient to make an animal goofy-looking for comic relief. (And in the case of Jiminy Cricket, I think Disney would rather draw, and people would rather look at, a humanoid with a weird head than an actual insect.) [0] "the uncanny valley is the hypothesis that human replicas that appear almost, but not exactly, like real human beings elicit feelings of eeriness and revulsion among some observers" https://en.wikipedia.org/wiki/Uncanny_valley https://en.wikipedia.org/wiki/Uncanny_valley
- speps 10y agoThe Taichi library linked [1] on HN recently has a MIT licensed APIC implementation here : https://github.com/IteratorAdvance/taichi/blob/master/include/taichi/dynamics/apic.cpp https://github.com/IteratorAdvance/taichi/blob/master/includ... [1]: https://news.ycombinator.com/item?id=13325190 https://news.ycombinator.com/item?id=13325190
- a_c 10y agoIn the video, it is mentioned several times "stability" and "noise". Can someone explain what do these two terms refer to in the sense of particle simulation?