We 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 :-)<p>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.<p>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.
"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.<p>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.<p>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.
Also coming into play during Moana is the hyperion rendering engine, which was first showcased in Big Hero 6:<p><a href="https://www.disneyanimation.com/technology/innovations/hyperion" rel="nofollow">https://www.disneyanimation.com/technology/innovations/hyper...</a><p>Also, here's an article containing some stills from the movie:<p><a href="http://blog.yiningkarlli.com/2016/11/moana.html" rel="nofollow">http://blog.yiningkarlli.com/2016/11/moana.html</a>
I 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?
Why is it that we can accept expressive/cartoonish looking characters but need to have the most realistic environmental rendering (light, physics effects)?<p>I challenge the studios to be imaginative and equally expressive on the latter. Give us the miyazaki equivalent in 3d animated films.<p>Don't take fthe easy way out by emulating reality. Put true art into it
The Taichi library linked [1] on HN recently has a MIT licensed APIC implementation here :<p><a href="https://github.com/IteratorAdvance/taichi/blob/master/include/taichi/dynamics/apic.cpp" rel="nofollow">https://github.com/IteratorAdvance/taichi/blob/master/includ...</a><p>[1]: <a href="https://news.ycombinator.com/item?id=13325190" rel="nofollow">https://news.ycombinator.com/item?id=13325190</a>
A little off-topic, but this site's cert appears to have a revoked intermediate authority. Pic: <a href="http://i.imgur.com/lIseT66.png" rel="nofollow">http://i.imgur.com/lIseT66.png</a><p>But no-one else seems to be complaining about this so I wonder if it's just me?
In 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?
This 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.