David Rosen of Wolfire Games explains how simple procedural techniques can produce fluid, interactive character animation from very few keyframes. Examples come from Overgrowth, Receiver and Black Shades, from his 2014 GDC session.
Why Hacker News points people here: HN points to it as a concrete case of procedural animation that keeps characters responsive, often in threads about Overgrowth and game feel.
“Here's a video I've enjoyed of David Rosen giving a presentation at Game Developers Conference 2014”HN comment, 2022
“David Rosen pulled off quite a few little masterpieces”
Talk by the Overgrowth developer on natural, responsive character control.
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> this video David Rosen pulled off quite a few little masterpieces -- his gamedev competition entries always had fantastically unique aspects. I cannot believe "Black Shades" was almost 20 years ago! (I have no affiliation, but I am glad to see link is still alive and kicking!) Lugaru and later Overgrowth have been the outcomes of what can only be called a decades long obsession with getting the player controls just right, allowing very natural and responsive control and movement, through creating emergent behaviors from first principles, resulting in a rich and natural interaction with the environment (and other characters, see the fighting mojo), in contrast to the many, many AAA titles that just constantly break the immersion through unnatural, jarring behaviors and frustrating limitations.
RecommendsneandrakeApr 2022
“Here's a video I've enjoyed of David Rosen giving a presentation at Game Developers Conference 2014”
David Rosen's GDC 2014 presentation on procedural animation in Overgrowth.
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Here's a video I've enjoyed of David Rosen giving a presentation at Game Developers Conference 2014 going over procedural animation used in Overgrowth. this video
RecommendsKronisLVApr 2022
“some of their approaches were immensely cool”
Procedural animation built from just a few keyframes.
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Not only that, but some of their approaches were immensely cool, they used procedural animations from just a few keyframes, have a look at this video that someone else linked a while back "Animation Bootcamp: An Indie Approach to Procedural Animation": this video
RecommendsturtledragonflyJan 2024
“In that example, they do the character's physics first (just a ball), then match the animation to it.”
Shows physics driving animation speed via a surveyor wheel approach.
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Not the person you asked, but here's a video you might like: this video In that example, they do the character's physics first (just a ball), then match the animation to it. The animation speed is controlled by a "surveyor wheel" approach — go to to 336s in the video for that part. So, the animation speed is derived from the physics, rather than the physics speed being derived from the animation. I wouldn't call that "IK" exactly, which would be more for things like matching the foot to individual stair steps as the character walks up them, or such. But I suppose in a broader sense it is, since you're deciding on a physical goal a-priori, then forcing the animation to match that goal.
Cites itomgketchupDec 2021
“sometimes keyframes and realistic constraints can get you there”
Procedural animation approach avoiding bespoke animations in games.
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this video It's definitely possible to "not bash into walls" You don't always need to have bespoke animations- sometimes keyframes and realistic constraints can get you there. I think Unity is working on a framework for natural human animation.
Cites itarran-nzApr 2022
“Looking forward to dive into the procedural animation system David talked about at GDC.”
Happy to see this! Looking forward to dive into the procedural animation system David talked about at GDC. [0] [0]: this video
Cites itdarzuNov 2023
“never at the cost of game responsivity”
Wolfire's philosophy that animation must not hurt player control.
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I’ve always preferred the Wolfire approach[0]: animation should “do no harm” to player control, it’s only there to add flavor, never at the cost of game responsivity [0] this video
Cites itdymkNov 2023
“Overgrowth was doing this in 2009.”
Overgrowth developer's GDC 2014 talk on procedural animation and IK.
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The keywords you're looking for are "procedural animation" and "inverse kinematics" - Overgrowth was doing this in 2009. The developer did a presentation at GDC 2014 on it: this video
Cites itrootlocusMay 2026
“He's talking about animations in particular, but I feel that should be a core pillar for any game designer.”
Principle of doing no harm to gameplay with animation.
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While I agree it's incredibly jarring in some games, I'm always thinking back at a presentation by David Rosen on procedural animation: "First, do no harm to the gameplay". He's talking about animations in particular, but I feel that should be a core pillar for any game designer. Many things are unnatural in games: you don't instantly recover from a beating by eating one apple in real life, but we're ok with it in games because it makes the gameplay fun. this video
