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The water technology behind Avatar: The Way of Water (unity.com)
168 points by oumua_don17 on March 12, 2023 | hide | past | favorite | 97 comments



Fascinating, 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

[2]: https://www.youtube.com/watch?v=Sdzksxe4rio


You mention Jurassic Park, but the fact is that movie wasn’t doable with animatronics alone. The most memorable shots in that film are CG.

I also contest your assertion that the results are more impressive than todays CGI. That’s some rose tinted nostalgia, but there’s no way to replicate some of the advanced motion and realism like the latest Planet of the Apes or Avatar with animatronics. The range of motion required is just not safe to do or cost effective.

Safety is a big one. Having an animatronic T-Rex chase a car at speed in the rain is not physically safe to execute in the same space as your main actors. The requirements are at odds. To work in rain requires materials that are hard to move, to move fast requires lighter materials and heavier motors. All of that is a giant weight hurtling at your talent. Use of lighter materials also makes them less durable or more expensive.

Furthermore, most animatronics and practical effects in film today are replaced. As much as people sell the allure of “this film is done practically”, the majority of it gets replaced with CG in post. The new star wars films tried that angle with BB-8 and Top Gun Maverick claimed the same, but they practical elements people laud were CG in the final film.


But at least the actors have something to work with, rather than having to imagine it. This makes a huge difference.


Nearly everything on a movie set is wildly fake. Imagination is required even for conventional acting. The whole job is "telling the truth under untruthful circumstances".

It can require a different toolset when it's just you and a blue screen, but in many ways it's the same craft that every actor develops anyway.


Villeneuve (Dune director) is amazed at the performances Cameron gets out of his actors with a green screen. One thing he does is "sense memories": he took the cast hiking in maui, to concentrate on and memorize the smells and textures of the jungle - to re-experience when shooting.

James Cameron & Denis Villeneuve on 'Avatar', 'Dune', and Pioneering CGI | Directors on Directors https://youtube.com/watch?v=RgZQK7cfx_0?t=14m30s


Sense memory is one useful tool in the director's toolbox. Some actors don't like it, because what you're seeing is their memory rather than the character's memory. They feel that it creates inauthentic performances. I know that may sound silly, but a lot of acting technique sounds silly until you realize that they're trying to not just rely on their own habits. That's what leads to actors being accused of "playing themselves in every movie".

(It also leads to directors abusing that privilege, getting "real" emotions in highly negative situations. Like the way Shelley Duval was reportedly terrorized by Stanley Kubrik while shooting The Shining.)

The director has to assemble the team that they want, who will respond to the toolkit that they're using. In the end it doesn't matter what it takes, as long as you get the shot you want in the can. (And complying with ethics, a thing that has too often been ignored.) I'll sometimes even use the worst tool a director has, feeding actors line readings, though only when they ask and nothing else has worked.


I don't see how that changes the point. Actors are still helped by not having a blue screen, and thus make a better performance.


They're not helped, but they're not hurt. They're used to delivering lines to empty space, even in conventional work. It's all of voice acting. Many performances are re-dubbed latter in a studio, where they have better control over the sound. Two-hander scenes are often done without both scene partners present; a stand-in is used for the over-the-shoulder shots, and their lines delivered by a production assistant off camera.

The point is that actors are used to imagining things. Ian McKellen didn't need an animatronic Balrog; he had no trouble delivering his lines to a tennis ball (which told him where his eyeline should point). It's all in a day's work for an actor.

It does put requirements on the director to visualize the scene for the actor. You can see that fail in Phantom Menace, where very talented actors deliver terrible performances not because of the blue screen but because they were given no direction. The director's job is always to convey what the actor needs to give the performance they want, and that can be nothing more than words.


> They're not helped, but they're not hurt.

Sorry, despite your nice exposition I still don't believe it. If you really think a blue screen doesn't negatively impact acting performance then it would require some kind of scientific experiment to convince me.


I'm not sure it's the kind of thing that really admits scientific evidence. By the metric of "dollars earned" or "jobs hired" actors of every different school of acting get jobs, and I doubt it makes a measurable difference at the box office.

It's an art so the techniques that work are the ones the artist chooses. I'm sure there are some who are happier with an animatronic and others who would just as soon scream at a production assistant on a ladder.


By the same token, do you have scientific evidence that they’re helped by not having a blue screen?

One person is clearly talking from experience of working with actors here (if you’re unaware of the person you’re replying to)


> By the same token, do you have scientific evidence that they’re helped by not having a blue screen?

Yes, it is clear that the person I'm replying to has more experience in this field; I'm just a "simple consumer" of movies. However, having experience can sometimes blind you from inconvenient facts. I think the burden is on the industry to prove that new technologies have no negative effect on the end product.


The effect on the viewer is more important than the actor. It's our job to make it interesting no matter what the circumstances. You are just supposed to enjoy it (enough to spend your money on it).

Audiences definitely like practicals, even when they aren't as realistic. People adore Baby Yoda even though it's obviously a puppet ... in fact because it's obviously a puppet.

They also react very positively to the Volume, which is so much better than blue screen even though it's just as fake to the actor. (They're usually not even looking that direction.)


That can be handled in many other ways, including having people in suits as standins.

Often, that’s better than animatronics because they can move faster and react to the actors better.

What is shot on stage doesn’t have to be what’s used in the film, and it’s a common mistake that people who are critical of CGI make.


> The most memorable shots in that film are CG.

I know it used CGI in some shots, but I disagree that these were the most memorable. Close-ups of the T-Rex, the creeping raptors in the kitchen, the sick Triceratops, the expanding neck frill of the Dilophosaurus, etc. These were the most tense and impressive shots IMO, and all were practical (even though they were historically innacurate). CGI was used mostly for wide shots that needed to show movement, which wasn't practical or sometimes even possible with animatronics.

> I also contest your assertion that the results are more impressive than todays CGI. That’s some rose tinted nostalgia, but there’s no way to replicate some of the advanced motion and realism like the latest Planet of the Apes or Avatar with animatronics.

I don't disagree that nostalgia is a big part of it, and the fact that back then these were truly ground-breaking shots we hadn't seen before. Each film did things slightly differently, and VFX weren't as accessible as today. Still, there's something raw and, well, real about an actual physical entity that actors interact with. The lighting and physical properties are always correct, and assuming the makeup and robotics are state of the art, it really can trick our brains into believing these are real objects much more than CGI could.

For example, take the sick Triceratops scene[1], and compare it to 2015's Jurassic World[2]. Sure, the CGI versions are more life-like, but they look completely fake. The lighting and shading is off, the interactions with the real world is limited and unrealistic, etc. In contrast, the scene from 1993 still looks impressive today, even though the movement is limited, and it arguably looks a bit stiff. State of the art CGI today is much better, though[3], but still slightly off in a few places.

This can possibly be blamed on "bad" CGI, but I'd argue most usage in movies falls into this category. Even the creatures in this new Avatar, while incredibly detailed and life-like, look artificial, and like they don't belong in the world around them (which is, ironically, also CG). It looks like an animated, instead of a traditionally shot, film. Which doesn't mean it can't be enjoyable, it's just a different experience. For me, it crucially lacks the awe-inspiring moments that films with practical effects often have. I realize that most of these shots couldn't be possible with practical effects anyway, but I appreciate when directors make an effort in using mostly practical effects, instead of defaulting to doing everything with CGI.

As another example, consider All Quiet on The Western Front[4]. According to the VFX lead:

> The overall VFX mantra was to allow the footage from principal photography to serve as the primary material for compositing, as opposed to creating CG elements in VFX to augment the scenes. “I believe that adds to the visceral, immersive quality of the film,” Frank Petzold explains. “So in other words when, say, there was an explosion scene, we did not entirely rely on CG models.” Rather, the team used photographic elements as the primary foundation, implementing CG simulations to augment principal photography. The effect was naturalistic, and the integration aimed to be seamless.

I think this is the right approach to take, and the film is much more immersive and enjoyable because of it.

[1]: https://www.youtube.com/watch?v=tYm7xeg27Rw

[2]: https://www.youtube.com/watch?v=2CJL7rKJI18

[3]: https://www.youtube.com/watch?v=le0iiWwdeeE

[4]: https://www.youtube.com/watch?v=hf8EYbVxtCY

[5]: https://www.fxguide.com/quicktakes/all-quiet-on-the-western-...


The raptors that are CG in most of the shots that aren’t just their heads? Like the entire sequence where they chase the kids…

you’re also comparing things without considering how the process created them.

Avatar wouldn’t look any more real with practical work. It’s just not possible to make robotics today that can have that level of articulation and micro expression. the reason it doesn’t look “real” is because the film makers didn’t want it to look real. It’s meant to be fantastical.

You claim most CG is bad in films but I’d argue that you, like many others, glomp onto the bad CG and ignore all the fantastic CG that you don’t notice.

How many people do you think noticed that the entire environment they’re in isn’t real in these shots? https://youtu.be/V5mS7BHmZJI

Often what people consider “bad CG” is overly apparent CG. This can be down to three things:

1. Budget. Both money and time.

2. Deliberate Aesthetic choices

3. Directors often put CG more in your face than practicals

Practicals wouldn’t make a difference there because they’d fall prey to the exact same issues which is why they’re often replaced in post anyway.

Aesthetics are a big one. The visual style between the original Jurassic Park trilogy and the Jurassic World trilogy is different. The new trilogy is significantly more fantastical in style and lighting. This is why you can’t just randomly compare shots between different films. They’re created by different teams with different goals. You need to compare against the raptors etc in the same film or where similar choices were made.

When people say “I wish this was done with practicals”, what I think they mean is “I wish this was better” but ignore the why.


The Hunt For Red October never got wet. The underwater scenes were miniatures with smoke floating to give the appearance of water. Listening to the stories of the people working on these types of models and the details they put in is so much different than someone at a computer with a 3D app.


Indeed:

“Making of "The Hunt for Red October" - Behind the Scenes” https://www.youtube.com/watch?v=2_epfA20dOY&t=21m55s

“HUNT FOR RED OCTOBER miniature effects part 1” https://www.youtube.com/watch?v=V5Npc6GsUeQ

“HUNT FOR RED OCTOBER miniature effects (part 2)” https://www.youtube.com/watch?v=MGu8qcI7r-I


Yeah, it’s too bad the story was so terrible. It’s a shame when there is a mismatch with the effort that went into the tech vs the writing.


I quite liked the story. Maybe a little long. Most people I know liked it too.


A good 1/3 of the runtime was James Cameron going "look what our tech can do".

And I actually didn't mind, the CGI was gorgeous.


It really is such a shame given just how much money got poured into the project that they didn't allocate even 0.1% to writing an actively good story.

At this point, I think that while Cameron has great visual taste, he simply just doesn't have any literary taste at all. I believe he actually thinks these horribly banal, cliched stories are genuinely good.

It's gotten so bad that it makes me retroactively wonder whether he actually wrote "Aliens" and who the real author is.


I don't understand this criticism. The story was amazing.


Do you mean that you don’t agree with the criticism, or that you don’t understand why someone would dislike the story? I feel like the former is the more understandable sentiment, since the latter is just a matter of personal taste.

After a quick read of critic and user reviews through metacritic, the complaints seem pretty consistent regardless of how I personally feel about them. A ton of them say the plot was barebones and predictable. Even the glowing reviews from critics seem to mention that the plot only gets the job done.


Being cliched and predictable isn’t even the biggest problem. The original Avatar story was cliched and predictable yet I enjoyed it. This Avatar 2 story on the other hand doesn’t even make sense. The kids were captured and rescued three times in a single movie which is beyond ridiculous. Quaritch had his hostages but kept making empty threats and basically stood there watching his men taken down around him without doing anything. The water clan simply disappeared halfway into the final battle while clan leader’s daughter was still held hostage. What a mess.


Having rewatched A1 a few times in the past few weeks (my kids rediscovered it), the original's story really doesn't make much sense if you think twice.

Once I understood that in both cases the story is there just so Cameron can do his worldbuilding, I enjoyed both films very much.


I have watched A1 maybe five to six times. There's the occasional leap of faith (like the literal leap of faith onto Toruk), but overall it's a reasonable story for a movie. (I try not to think about the white savior theme.)

A2 is a different beast. The conflicts in A2 can be described as:

- Quaritch captures kids.

- Quaritch: Sully, come alone and surrender, or I kill your kids.

- Sully doesn't come alone and doesn't surrender. Quaritch leaves kids alone. Quaritch's men die, kids rescued.

- Quaritch captures kids, again.

- Quaritch: Sully, come alone and surrender, or I kill your kids.

- Sully doesn't come alone and doesn't surrender. Quaritch leaves kids alone. Quaritch's men die, kids rescued, again. One dies from battle wound.

- Quaritch captures kids, again.

- Quaritch: Sully, same deal despite everything, come alone and surrender, or I kill your kids.

- Sully doesn't come alone and doesn't surrender. Quaritch leaves kids alone. Quaritch's men die, kids rescued, again.


Maybe he was bluffing because he knows dead hostages are worse than live hostages?

If you can stomach Quarich being okay with being reborn into the thing he hates the most, or everyone important that died in A1 being reborn, or the fact humans don't simply nuke the Navi from the orbit, or the fact that unobtanium is not as important as miracle whale oil, .... then Quarich bluffing and being called on it and then trying to repeat the bluff is not SO far fetched.


The first trailer kind of telegraphed that it's going to be about family and stuff but oh boy. Sounds bad. I haven't seen it yet. Didn't want to torture myself with 24 FPS imax


It's beautiful scenery, awesome effect and impressive world building. Do not watch it for the story or Avatar 2 will chew you up and spit you out.


What smurfs in space 2 bro? You must be joking cuz, the dialogue and story are atrocious.


Yes they are blue and in space. You sound like a very shallow person.

It's a story about spirituality and nature and community and family that explicitly advocates for eco-terrorism against the American government.

But none of that matters because they are blue, lol. People aren't blue. How silly.


> It's a story about spirituality and nature and community and family

It’s a _clichéd_ story about all those aspects. “We are a family” or a variation thereof is the most repeated sentence in the movie. The evil guys are evil, 100%, no nuance.

My humble opinion is that the movie is visually stunning but too predictable, but I’m not a fan of most movie where “things go boom” or “fighting to death” is a substantial component of the plot… so there’s that.


Unpredictability is not a universal virtue in storytelling. You pretend you are above spectacle, but your enjoyment is so dependent on the spectacle of clever twists and subversion of expectations that you can no longer appreciate the value of a masterfully told straightforward story.


I don’t see where I pretend to be above spectacle: I highlighted a correlation (most movie with those things are not of my liking), not a prerequisite. I’m actually a big fan of James Bond movies, classic ones (very “shallow” by modern standards and still good imo) and new ones too, and there’s plenty of fighting and explosions in those.

I explained why to me it was a boring three hours in a very comfortable movie theatre armchair, so that you see why some people didn’t actually enjoy it as much as you did. On the masterpiece part, I’ll agree to disagree :)


The first Avatar had zero lasting cultural impact and this one will be the same. Name me one quotable line from either film. “I see you” lol

You seem like a very shallow person if you think these films are any good.


S5E5 of “How To with John Wilson” (coincidentally, that I found a refreshing and even moving show that talks about human relationships - among other things - in a honest, down-to-heart way) disagrees with your assessment of cultural impact :)


Well first of all there’s only been 2 seasons of How To With John Wilson. I’ve seen the episode you’re referring to and the only thing it shows is some very sad, lonely and troubled people. I’d hardly call that a lasting cultural impact for a film that made almost 3 billion dollars and was then pretty much forgotten about.


Imagine thinking "the movie wasn't just a collection of pre-packaged memes to share on twitter like all other major movies nowadays" is a good criticism.


Imagine thinking cultural impact is Twitter memes.


What? You were the one that equated cultural impact with quotable lines. The fact that memability doesn't equal cultural impact is exactly the point I was making.


I presume the masterpiece Avatar triumphed at the Oscars and swept all before it.


Are you suffering from Post-Avatar depression syndrome? That would explain a lot!


Is the idea that someone would genuinely appreciate the artistry of an earnest movie without clever self-aware memable moments really that unthinkable to you?


Are you talking about the latest Avatar movie? I really liked the story.


You knew what you were doing when you wrote this you anarchist.


Did you even see the movie?


The story was really generic. I'm surprised so many disagree.


Right? Another blockbuster movie openly advocating for eco-terrorism against the American government? Yawn. When will they finally think of something new?


I don’t get it. The government invaded a sovereign world and they don’t have the right to fight back?

Edit: I can’t find this talking point on the internet in the usual places anywhere.


I don’t see anyone saying they don’t have the right to fight back. That’s why it’s an interesting story for me, it shows why eco-terrorism can be a rational answer. Also fun to compare avatar themes with his ex-wife’s film that came out the same year, zero dark thirty.


Is that exactly what the person I replied to was complaining about?


I think the person you replied to was being sarcastic. They were pointing out that the ideas presented in the movie are anything but generic for major blockbuster movies.


Check out the YouTube channel Corridor Crew, I also liked movie magic and I think you'll like their content


Thanks! I've seen some of their videos over the years, but hadn't subscribed yet.


It's a different "magic" in recent films for sure. The images are visually pleasing, and have a kind of muscular, wet-and-glimmering look.

The old concept of animating physical objects to make them look like they're inhabited by a spirit and behave/bleed like real animals has been absorbed into motion capture and animation rigs.

We also used to love seeing people grow into new behaviours like luke in star wars. He was awkward and unsure of how he should act, and he grew into his new role as a jedi. Another example was Alan in Jurassic Park guiding people through the park by behaving in a manner that wouldn't get everyone eaten. But it's common for people to understand how to behave in action films and real life. The demand to see people learn a new set of behaviours, isn't such a strong pull to watch movies lately.

I struggle to imagine what a new-and-improved look for animated bones and lifelike animatronics would be? An engineer could make them stronger, better, faster and move more smoothly, but the higher experience people could want.. I don't know what it could be.


> even today, a discerning viewer can still tell CGI apart from live action

You can tell BAD CGI apart from live action.

https://youtu.be/bL6hp8BKB24


I don't disagree with the conclusion in that video. But my criticism is precisely when filmmakers rely solely on CGI for every aspect in a scene. When used in moderation, and to _augment_ practical effects, as in the original Jurassic Park, or All Quiet on the Western Front, then it can increase, rather than break, immersion.

Eventually, we'll reach a point when CGI truly becomes indistinguishable from reality, but even then I'd argue that using it for all aspects in a scene would undermine what makes the art of cinema "magic". After all, would it really be filmmaking, or animation, at that point?


I’m sorry but I vehemently disagree with the premise of your points. I think you’re still assuming that practicals could do it all and somehow CG is solely at fault for things you don’t like.

1. The practical effects on Jurassic Park weren’t simply augmented by CGI. The hero sequences had the main set pieces as CGI. Please tell me how you’d do the T-Rex chasing the jeep with practicals? Or something like gollum fighting with Frodo ? Or Davie Jones in Pirates?

In fact, when Jurassic Park came out: the CG elements were the hero’s in the news. This retconning of saying the practicals were the stars is rewriting history to fit a personal subjective narrative.

It almost put Phil Tippet out of a job, if Dennis Muren wasn’t a great friend. The news cycles and hype at the time were around all the CG sequences and how it wowed audiences.

2. It’s ridiculous to say animation isn’t a form of film making. It’s possibly the most pure form of film making. You craft every single detail, and make every single choice along the way. this kind of puritanical thinking of saying animation isn’t film making isn’t constructive. Are you seriously going to say that Toy Story isn’t film making? Or The Lion King? The little Mermaid?


> I think you’re still assuming that practicals could do it all and somehow CG is solely at fault for things you don’t like.

I'm really not. Of course sequences like dinosaurs running, or films like Avatar and LOTR couldn't be done without CGI. There's a reason these films weren't possible before CGI; the technology simply didn't exist to bring the author's vision to life.

> In fact, when Jurassic Park came out: the CG elements were the hero’s in the news.

Of course. Animatronics were nothing new, while CG of that level and scale was practically unheard of. I would still argue that those films elevated practical effects to another level, which should be equally lauded as the CG work.

> It’s ridiculous to say animation isn’t a form of film making.

That's not what I'm saying. I don't look down on it, and enjoy many animated feature films. What it is, though, is different to traditional film making, which puts it in a different category of entertainment. The production doesn't involve a physical set, live actors, cameras, makeup artists, and dozens of humans dedicated to capturing live performances. Instead it involves voice actors who mostly work in isolation, an animation director who mostly works with artists, and large teams of designers, animators, editors and technicians who bring the characters to life.

> It’s possibly the most pure form of film making. You craft every single detail, and make every single choice along the way.

Are you implying that traditional filmmakers don't? How is that constructive?

> Are you seriously going to say that Toy Story isn’t film making? Or The Lion King? The little Mermaid?

Like I said, not in the traditional sense.

My point is that once CGI becomes indistinguishable from reality, and most/all scenes are entirely created by computers, is it a live action movie, or an animation at that point? The line is already blurry today with movies like Avatar, but I still enjoy watching movies that make practical effects a priority, over those that liberally use it in every scene.


> Are you implying that traditional filmmakers don't? How is that constructive?

They don’t at anywhere near the same level of choices involved in animation.

That’s just the simple reality of making something that is a simulation. You choose the way light bounces even if it breaks physics. You can’t do that in real world content. You choose silhouettes and shapes that can’t exist in reality.

I’m not saying they don’t make changes. But your statement implied that Animation wasn’t filmmaking. It is. One isn’t better or worse than the other.

And CGI is already indistinguishable, when we give it both the budget and art direction that is required. It’s been indistinguishable for most non-biological things for a decade now. We can already make completely realistic creatures and in some regards, also humans. Humans are hardest to still do but creatures have had that milestone crossed ages ago.

The hurdle is having the time and desire to do so.

I think you are going out of your way to segment things, and place them on a ladder. These are all tools to make content.

Saying that CG is best when augmenting practicals is just reductive. Especially when you keep bringing up Jurassic Park where the CG elements were largely the stars, and practicals filled in the rest. Practical effects, CG in VFX, full on animated features…they’re all tools for a creative. They can all suck or be amazing.

This whole “practical vs CGI” battle is literally just a construct of marketing that people are fed as a form of virtuoso. The people who actually do the work aren’t concerned with this kind of putting one technique on a pedestal over another. They’re all just tools.


I won't drag on this discussion as we both surely have better things to do :), but just one last comment:

> This whole “practical vs CGI” battle is literally just a construct of marketing that people are fed as a form of virtuoso.

It's really not. I can have preferences as to which movies I enjoy more, can't I? _For me_, practical effects are just more enjoyable and immersive to watch. When CGI reaches that level of realism—and you're right that in many ways it already has—I would still appreciate the result more if I knew that the effects were done physically, with all the challenges that poses. With the advent of machine learning, CGI is being commoditized to a level where anyone can create high quality visuals. This is great in many ways, but at the same time, it requires a completely different set of skills, with arguably much less effort, and so I'll never appreciate it as much as the product done in traditional ways.

You're free to think otherwise, and that's fine as well. :)


You’re free to an opinion but I just think the foundation of said opinion is shaky.

Your latest comment also belies that you don’t particularly understand or appreciate how much work goes into making CGI. It’s not any less of an art form than practical effects.

The difference is that it gives a much higher degree of flexibility, but the artistry and technical ability required isn’t diminished in any form.


The 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.


Of course we did. This is why otherwise ordinary "Top Gun 2" was so massively successfull: lots of live action and practical effects.

I think we will lose it at all eventually. Today's audience is not making a big difference between movies and computer games, so the current disgrace of Marvel comic movies is just okay for them (old_man_yells_at_cloud.gif)


Tangential, 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


To be fair, the second person is more than likely pursuing more advanced education than a CS BSc (PhD)


> niche domains

I’m not sure if I would call movies and video games “niche”.


If you get a CS degree and end up doing UIs/forms in React then something along the way went very very wrong.


yeah 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


You realize that there are 2.7 million software developers in the US? Outside of the HN bubble, most are “dark matter developers”.


Completely 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 >.>


When 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.


That's the Leidenfrost effect. Maybe we'll see it in a Disney movie called "Leidenfrozen".


I think that the behaviour you're describing is due to the Leidenfrost effect!

https://en.m.wikipedia.org/wiki/Leidenfrost_effect


I 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.


The 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.


Unity 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).

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...

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/hfFlu...


It’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.”


Yeah, 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

- “Wave Curves: Simulating Lagrangian water waves on dynamically deforming surfaces,” presented at SIGGRAPH 2020 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

Code:

    for (const deck of __NEXT_DATA__.props.pageProps.entity.decks) if (deck.url) console.log(deck.caption, deck.url)


Thank you!


Cameron 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.


I wish they’d invested a little less on the technology and a little more on the writing.


It 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?


Actually it says it was done in Loki, which is explained in this journal article https://dl.acm.org/doi/abs/10.1145/3528223.3530058


[flagged]


I 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.


Unfortunately 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.


Why 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.


1. 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.


For 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.


This 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.


Yeah I admit I’m being childish. The first movie is so mediocre, I’m annoyed that anyone cares about this franchise.


Whether 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.


Corridor Crew covered that scene with the VFX Supervisor from Weta here: https://youtu.be/c4Gd0bR2kb4?t=383


It's actually an amazing movie about blue cats.


It'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.


So you haven't seen it.




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