How Trico Was Animated / Video Game Animation Study

How Trico Was Animated  /  Video Game Animation Study

The Last Guardian is the third game in a spiritual
trilogy directed by Fumito Ueda, formerly of Team Ico, who developed the games
Ico and Shadow of the Colossus, and is now part of GenDesign. The game is about a boy who befriends and
eventually commands a large fictional part-bird, part-cat/dog creature called Trico through a ruined, castle-like maze. One of the gimmicks is that Trico can act
independently while also obeying instructions, and that you must train Trico to listen to
you in order to solve puzzles and explore the environment. It feels like a combination of both Ico and
Shadow of the Colossus. One of the challenges the production team
faced was creating convincing movement for Trico as it freely explored the environment. And I think it’s safe to say they pulled
off a visual delight with the creature. Let’s take a quick look at how they achieved
Trico’s animation! Much of this information comes from a Japanese
presentation by GenDesign which was translated by Twitter user @brando_themando
for Jonathon Cooper’s Game Anim website, which is where I found it all, and Jonathon
Cooper’s Game Anim book, which I recommend you check out. So I’ll list my sources in the description
below if you want to learn a bit more about The Last Guardian’s development. Despite the realistic motion of Trico, no
motion capture was involved in the animation process. Instead, the team spent some time deciding
which creature they’d take influence from in order to mimic its movement, and fill in any gaps in information with procedural
animation, but we’ll come to that in a bit. They started with a cat as a reference point
for the majority of movements, stating that people around the world love
cats, even if they don’t always listen to you, and it was also a good reference point for
having their own creature climb up high structures and squeeze into tight spots. Other animal movements were used depending
on the action Trico performed, and this is why motion capture would have
been difficult to implement with the animation process. They then thought about the sense of scale
and size. Scaling up the movements of a cat to the size
they wanted wouldn’t have been as convincing, so they looked at big cats like tigers and
how they moved to give a more realistic sense of scale. The end result was movement that didn’t
reference one single existing creature, instead using a collection of different movements
that created something familiar but fantastical and new. But that wasn’t where it ended. There’s something very realistic about the
movements of Trico. As a character, it feels very alive. This is where the team’s use of Procedural
Animation came in. Procedural Animation is producing motion in
real-time using in-game calculations. You’ll often see this in games where a character’s
limb or appendage automatically connects to a surface. The boy does this himself when he’s near
a wall or surface. This type of calculation is called inverse
kinematics, and it’s a bit difficult for me to explain
technically, but it very basically ensures that the joints of a skeletal frame move correctly
and allows correct connections between characters and their environments. This procedural animation is what allows Trico
to explore its environment naturally. The animators will have programmed a walking
motion into Trico, which would work well on a flat terrain, but
animating that same motion on varying levels of terrain would be incredibly laborious and time consuming, By adding procedural animation, this allows
that same movement to happen on a different terrain and still stay close to the original key pose,
and thus look “correct”. So if Trico has to step over a broken pillar
or something, he’ll still have that same walk cycle, but
whichever paw lands on the obstruction, it’ll step onto it instead of clipping through
it, and it won’t affect the other paws or the overall motion. This results in a very natural action. If you look closely, you can often make out
each part of Trico that’s being mathematically controlled depending how it’s standing, where it is
and what it needs to do next. The next part of making Trico feel alive was
adding artificial intelligence. For instance, Trico would often be interested
in something, and move to that interest, and then react
to it accordingly. But objects of interest were based on priority,
with Trico paying more attention to high priority objects first, and then directing attention to the interest
that’s next in line. This is what gives Trico its apparent natural
inquisitiveness to its surroundings. The environment was a big factor as to how
Trico would react to interests. For instance, if there’s a barrel, then
Trico will choose how to get to it and then eat it. If there’s not enough space, then Trico
would think of a way to get at it. If it got stuck trying to reach it, then it’d
ask for help from the boy. The actual action of looking at a point of
interest is literally called ‘look-at’, which is linked to inverse kinematics. Particularly for Trico, the designers felt
that simply moving and rotating his neck and head to look at something gave a somewhat robotic feel, and added in
a method which fixed the head position, followed by the neck, which they called “lion-dance
control”, which references some real world animals that
can control their bodies while keeping their head still. The designers felt this added a bit more realism. Corrective action was another form of calculation
that kept Trico feeling real. If it’s line of sight to the point of interest
is obscured or altered then it’ll readjust its body to a sturdy
and realistic position so it can observe the object clearly again. Making calculations within the model frame
of how to move the body while referencing as closely as possible the original key pose. Generally, Trico’s AI involved identifying
a point of interest, how to get to the point of interest, and then
making a decision about the point of interest, and the procedural animation built into the
motions surrounding those choices added to Trico’s realism. But the reason Trico felt so real wasn’t
just because of his artificial intelligence and procedural animation. Calculated movements can only do so much, they can’t replicate or produce strong,
interesting poses. The corrective calculations which gave Trico
realistic movement would only work if there’s manually animated keyframes to
begin with. Each new calculation regarding the environment
still has to stick realistically to the key pose that’s been manually animated into Trico. The magic bringing Trico to life was a complex
mixture of artificial intelligence, procedural animation, and good old fashioned animation by hand, using real world animals as reference points
to create strong dynamic key poses. We leave the game remembering Trico as a character
much more because of this multilayered production into his movement. And that is how Trico was animated. Thanks for watching this one, and thanks to
my patrons for funding this episode. Let’s pick one….Ben Williams, thanks mate. Good name, I like the double L in your surname
there, and I like the ‘B’ in BEN. It’s good. Okay, have a great festive period everyone,
and see you in the new year! Loveyoubye!

Comments (32)

  1. Shame that when Trico is on screen the game drops to 20 fps.

  2. Another Great video Dan ! Hopefully you'll do animations for the shadow of the colossus one day ,that would be great !

  3. thought this was about pokemon

  4. is that unity where the stuff is being moved around, to show how he looks, and changes lim placement?

  5. Great stuff Dan. Trico is truly one of those gaming gems that as time passes, the character will be forever remembered and loved by players because of how complex and nuanced he turned out to be. (Or she? Who knows lol)

    What a treat The Last Guardian was. Such a unique game from the stuff generally releasing on a yearly basis.

  6. So Trico is 20% cat, 10% dog, 5% bird and 100% adorable baby.

  7. It was a trick-o process

  8. I'd like to know how to do Procedural Animation in Unity like they showed, but I don't know how to do it, anyone got any tips or links that could help?

  9. Fantastic video as always! I imagine we'll see a lot more of this kind of procedural generation in games going forward.

  10. Being a heartless bastard I’m not into Uedo’s work despite his excellent pedigree (he worked for Kenji Eno’s WARP) and yet I found the video thoroughly interesting I must say. ?

  11. Oh man, the timing of this video is perfect! I just started playing The Last Guardian again this morning, as I never got round to finishing the game when it first came out, and I’ve been in awe of the incredible animation the entire time I’ve been playing. Thanks for the amazing video, as always. 🙂

  12. Dan, this is awesome! Question: could PA and IK be applied to a fighting game to improve the animation of being hit, or blocking an attack? Or is this done already? I noticed that SF5 chars have a different block animation depending on where the hit lands but I have a suspicion that it's based on key frames and nothing else…

  13. Great work, as always!

    If I recall correctly, SOTC did had some version of Procedural Animation at work with the Colossus. The bird boss can be one of the examples.

  14. I've been looking forward to this one! Really interesting stuff there. I've always appreciated why it took so long to make, but this just highlights some of the problems they had to get round. It's a technical marvel. I'm gonna have to play it again now! Thanks for the shout out dude, I'm glad the double 'L' pleased you.

  15. I love how the game conveys the dynamic between boy and monstrous huge hairy thing. Like yeah, you see him as this wild ugly beast, but you feel.that inside him is something almost beautiful, God like even…
    Yeah, God of war PS4 is such a great game

    I should try last guardian as well

  16. Trico is fascinating, but also kind of unnerving..

  17. The Last Guardian's Trico was always something I found cute. When I first heard of the game, Trico looked great. Mainly the fur effect and the overall windy feeling.

    Great video! =)

  18. Important to note that Team Ico were among the first developers to use Inverse Kinematics with Ico and Colossus

  19. Curious to know the concept used for the traces on the feet. Clearly its not just a simple trace downward to offset the foot height. Could be a series of traces in the direction the foot bone is moving to "map" the terrain? Perhaps the system is able to know the future plant location of each foot, and can run a series of traces between the current plant and future plant…Either way, probably the best implementation of limb IK I've seen in a game. Never remember seeing any overstretching either.

    Id be willing to bet most in-game animation is being applied to a runtimeIK-rig, where only key parts of the body (upper and lower abdomen, feet, and head) are actually animated, while everything else (like the spine, neck, and elbow/knees) are under a bunch of different constraints. That way those parts can be offset and everything else works automatically. There's probably numerous secondary layers as well to play additional motion across areas of the body, which help to mask transitions and provide additional overlap. Breathing and idle swaying is probably on its own layer, and the ears, wings, and facial bones probably each have a layer as well. The constant motion on the feathers really sell everything though, as they provide additional visual noise to hide unnatural movements (as is common in many procedural approaches) if they were to ever occur.

    Designing a game around a large animated creature that dynamically interacts with it's environment, while being under constant close observation is such a wildly ambitious goal, yet they nailed it.

  20. Please get a mic that reproduces high frequencies better, and use less noise reduction. It is too hard to understand you without consonants.

  21. This game is still one I want to play. I know everyone complains about Trico, but I could easily get lost in enjoying time with him. All the petting, all the food, everything Trico wants, Trico will get.

  22. This video was a delight. Thank you.

  23. I ADORE ur work Dan!!!

  24. I forgot how incredible this game was. Thank you for covering it!?

  25. Thanks for the explanation and for citing all the sources, it will be an interesting read.

  26. i love the environments too

  27. This is such an underrated game.

  28. Oh look it's the never ending story the video game

  29. I can see why it took Team Ico so long to release the game, since I don’t think I have seen any other games try to use procedural animations outside of weather effects or little things like preventing clipping into objects.

  30. Yay! The episode I was wishing for the most!

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