10 ms·
The water technology behind Avatar: The Way of Water
- djtango 4y agoCompletely aside from Avatar, I'm hoping the tech for things like underwater motion capture and this water modelling brings about a renaissance in underwater themed games. I'm looking at you Monster Hunter and also Blitzball >.>
- deleted 4y ago[deleted]
- name-form 4y ago[flagged]
- vlunkr 4y agoFor real. There were people debating online about whether a shot in the trailer was real or not, but it was someone’s arm and a leather harness thing. Why does that even need to be CG? Literally paint someone’s arm blue.
- nighthawk454 4y agoCorridor Crew covered that scene with the VFX Supervisor from Weta here: https://youtu.be/c4Gd0bR2kb4?t=383 https://youtu.be/c4Gd0bR2kb4?t=383
- dagmx 4y agoThis is highly reductive. In that shot, he’s interacting with virtual water, sitting on top of a virtual creature and the top of his arm is virtual as well. The argument online was whether it was fully CG or partially CG. Your version is one that nobody would pick because it wouldn’t work in the context of the shot. The anatomy of the Navi doesn’t map exactly to a human, especially the musculature. You’d also need the geometry in shot as well for interactions with other virtual elements. It’s very easy to be an armchair expert. It’s much harder once you start delving into the intricacies of the work required.
- vlunkr 4y agoYeah I admit I’m being childish. The first movie is so mediocre, I’m annoyed that anyone cares about this franchise.
- dagmx 4y agoWhether or not the film is subjectively bad has no relevance to whether or not the technical work on the film is amazing and worthy of discussion. This is HackerNews not a film critique site after all.
- brookst 4y agoI mean, Cameron seems to enjoy pushing video and CGI technology forward, and audiences seem to enjoy it, so… why not? Sneer all you want, but it seems like something lots of people enjoy making and viewing.
- anon_cow1111 4y agoUnfortunately the article does note one important (depressingly predictable) part- >A majority of the water tools developed by the team sit within Wētā’s proprietary simulation framework, Loki. ...Makes a lot of the advancements moot when they're going to remain buried in a place completely inaccessible to anyone without a hundred million laying around.
- dagmx 4y ago1. Unity are planning to make Wētā’s tools available for a fee. So it’s not going to be locked away forever. 2. As good as their tools are, they’re not something that can’t be replicated in something like Blender.
- brookst 4y agoWhy don’t you go invest the time/money in a proper open source version? If these folks are going to be so unreasonable as to try to recoup investment, you should have no problem getting traction.
- cyborgx7 4y agoIt's actually an amazing movie about blue cats.
- mtlmtlmtlmtl 4y agoIt's very mediocre, cookie cutter, dumbed down, hitting you over the head with social messaging movie. And so boring too. I've never been able to sit through it without falling asleep.
- gsich 4y agoSo you haven't seen it.
- ffhhj 4y agoWhen I heat the pan and throw some drops of water on it, the drops "dance" and emit a hissing sound. This effect haven't been realistically simulated and would be a good pretext to shrink those blue aliens in the next movie.
- speed_spread 4y agoThat's the Leidenfrost effect. Maybe we'll see it in a Disney movie called "Leidenfrozen".
- ginnungagap 4y agoI think that the behaviour you're describing is due to the Leidenfrost effect! https://en.m.wikipedia.org/wiki/Leidenfrost_effect https://en.m.wikipedia.org/wiki/Leidenfrost_effect
- imiric 4y agoFascinating, thanks for sharing. It's amazing how many novel techniques went into the film. I haven't seen it yet, but looking forward to it. One of my favorite TV shows as a kid was Movie Magic. Back in the 90s, most effects were practical, rather than CG, and it was interesting to learn about the various techniques used to achieve the results. From matte paintings, foley sounds and miniature sets, to animatronics and pyrotechnics. There were entire industries dedicated to this, which were replaced—practically overnight—by computers. While there was a rough patch of awful CGI in the 90s and 00s, and the tech has certainly come a long way since then, even today, a discerning viewer can still tell CGI apart from live action. I feel like we lost some of that "magic" in the process. Consider the animatronics used in Jurassic Park[1] and Free Willy 2[2]. They might be crude, stiff and surely very laborious and expensive to build, but the result on screen was much more impressive than today's state of the art CGI. Maybe we've been saturated and take VFX for granted today, but it's a shame that some of these practical effects didn't continue to improve, and are rarely used in modern films. [1]: https://www.youtube.com/watch?v=X8Fv3tQm_Os https://www.youtube.com/watch?v=X8Fv3tQm_Os [2]: https://www.youtube.com/watch?v=Sdzksxe4rio https://www.youtube.com/watch?v=Sdzksxe4rio
- echelon 4y agoThe amount of work that went into those orcas is insane. I appreciate all the work and dedication of those folks, but it feels like such a waste. Especially when the final film wasn't very good. The craft is admirable, but it was never scalable or equitable. Very few projects could benefit from this kind of budget and vision. The coming AI revolution will make this vastly cheaper than even CG, and it'll give more people a hand at storytelling. Without requiring fifty engineers a full year of their talents.
- iancmceachern 4y agoCheck out the YouTube channel Corridor Crew, I also liked movie magic and I think you'll like their content
- imiric 4y agoThanks! I've seen some of their videos over the years, but hadn't subscribed yet.
- arduinomancer 4y agoTangential, but reading about niche domains like this its crazy to think how different the things people do under the job of programmer Two people could get CS degrees and one ends up building UIs/forms in React the other is implementing “Lagrangian water wave simulation” Just totally different worlds
- archerx 4y agoIf you get a CS degree and end up doing UIs/forms in React then something along the way went very very wrong.
- yieldcrv 4y agoyeah one person makes a shit ton of money wondering if they needed a degree at all, and the other person ends up getting overworked for pennies and no equity in movies and gaming studios
- scarface74 4y agoYou realize that there are 2.7 million software developers in the US? Outside of the HN bubble, most are “dark matter developers”.
- antegamisou 4y agoTo be fair, the second person is more than likely pursuing more advanced education than a CS BSc (PhD)
- deleted 4y ago[deleted]
- nradclif 4y ago> niche domains I’m not sure if I would call movies and video games “niche”.
- deleted 4y ago[deleted]
- jahnu 4y agoIt’s sad that the videos are unavailable if you prevent tracking cookies. Over each video I get “This content is hosted by a third party provider that does not allow video views without acceptance of Targeting Cookies. Please set your cookie preferences for Targeting Cookies to yes if you wish to view videos from these providers.”
- hddqsb 4y agoYeah, and the video elements are created dynamically so you can't just find the video trivially by opening the DOM inspector. Here are the videos: - “Loki: A unified multiphysics simulation framework for production,” presented at SIGGRAPH 2022 https://www.youtube.com/watch?v=_2TBvSnsLD8 https://www.youtube.com/watch?v=_2TBvSnsLD8 - “Wave Curves: Simulating Lagrangian water waves on dynamically deforming surfaces,” presented at SIGGRAPH 2020 https://www.youtube.com/watch?v=FqCK5Gu-Op4 https://www.youtube.com/watch?v=FqCK5Gu-Op4 - Overview of “Guided bubbles and wet foam for realistic whitewater simulation” as presented at SIGGRAPH 2022. Video courtesy of Wētā FX. https://www.youtube.com/watch?v=60Dk5h_659s https://www.youtube.com/watch?v=60Dk5h_659s Code: for (const deck of __NEXT_DATA__.props.pageProps.entity.decks) if (deck.url) console.log(deck.caption, deck.url)
- jahnu 4y agoThank you!
- fsiefken 4y agoI wonder if UE5 or Blender have similar and perhaps competitive methods for the Loki water state machine in generating realistic water and mist. The article uses a lot of jargon: Navier-Stokes simulators, Lagrangian wave packets attached to spline curves, incompressible two-phase Navier-Stokes solvers on a Eulerian grid, and air phase representation by FLIP (Fluid Implicit Particle) and APIC (Affine Particle-in-Cell) solvers. I remember the Quake I water simulation, which I found amazing at the time. I knew water is hard to simulate, but understanding fluid dynamics and the above jargon seems hard to grok too.
- mkoubaa 4y agoThe techniques that control the way electrons flow in silicon is hard to grok. But that gives way to logic gates, that let you build CPUs with branch predictors. The way that branch predictors actually work in CPUs is hard to grok but how to write code that keeps their implications in mind is more approachable. Learning how to use libraries that leverage the above is even easier to grok. Technology is built upon a stack of useful abstractions, and the ability to understand in deep technical detail the entire stack is a super power. There's no reason why computational physics shouldn't work the same way.
- hyperthesis 4y agoUnity also bought SpeedTree, which did the vegetation in Avatar 1 (and in many video games). They bought Weta Digital in 2021 (https://blog.unity.com/news/welcome-weta-digital https://blog.unity.com/news/welcome-weta-digital). Blender has a FLIP plug-in I believe. The water in UE isn't great, but the "fluid flux" plug-in is surprisingly impressive for real-time water https://www.unrealengine.com/marketplace/en-US/product/fluid-flux https://www.unrealengine.com/marketplace/en-US/product/fluid... Computational Fluid Dynamics is a tricky area. The science (Fluid Dynamics) was worked out over 100 years ago, with the Navier-Stokes equations (3D partial differential equations). The engineering (the Computational part) is a whole bunch of complex and clever tricks, to overcome surprising problems like instability and dissipation, and often for some particular engineering trade-off (rather than being universally true). Avatar 2 seems to use an underlying FLIP simulation for the water (which uses a (eularian) grid for pressure, and particles for movement), with cinematic tricks on top: foam, bubbles, and smaller (lagrangian) waves superimposed. The Fluid Flux plug-in uses a simplified version of the Navier-Stokes equations, which represents the upward direction as an average - so it's 2D internally but looks 3D. It also just calculates once, instead of iterating. Both make it much faster. It uses this paper, which has several other tricks: https://matthias-research.github.io/pages/publications/hfFluid.pdf https://matthias-research.github.io/pages/publications/hfFlu...
- precompute 4y agoCameron hired all the competent, experienced CGI / animation people and the rest of the special effects industry hasn't moved ahead much since. It's even regressed in places.
- freediverx 4y agoI wish they’d invested a little less on the technology and a little more on the writing.
- tarr11 4y agoIt doesn’t say in the article how this was implemented. Was all this simulation done in something like Houdini or is there a custom engine Weta uses?
- mkoubaa 4y agoActually it says it was done in Loki, which is explained in this journal article https://dl.acm.org/doi/abs/10.1145/3528223.3530058 https://dl.acm.org/doi/abs/10.1145/3528223.3530058