Animation & Machine Learning at Epic Games. Ex Ubisoft La Forge. Programmer & Occasional Writer. https://theorangeduck.com/https://bsky.app/profile/theorangeduck.bsky.socialhttps://bsky.app/profile/theorangeduck.bsky.social/post/3mznhielqbs23Today's blog post is on a simple algorithm for computing collisions / intersections between two arbitrary SDFs. https://theorangeduck.com/page/simple-sdf-collisions Including a little web demo that can be fun to play with: https://theorangeduck.com/media/uploads/SDFCollision/sdf.html06 Nov 2026 13:12 +0000at://did:plc:ay6paf5o7pabd44vfgmzltcl/app.bsky.feed.post/3mznhielqbs23https://bsky.app/profile/theorangeduck.bsky.social/post/3mxup3msv6k2nI just added an appendix to my "visualizing rotation spaces" page with a couple of fun but more obscure representations: the cayley map and the cylindrical representation. Let me know if you know any cool uses of these! https://theorangeduck.com/page/visualizing-rotation-spaces#appendix14 Oct 2026 23:26 +0000at://did:plc:ay6paf5o7pabd44vfgmzltcl/app.bsky.feed.post/3mxup3msv6k2nhttps://bsky.app/profile/theorangeduck.bsky.social/post/3mt2esaad5k2iThe UE 5.8 release actually already contains lots of the Machine Learning Animation tools we've been working on over the years! Today we finally released an example plugin and bunch of tutorials covering how to use them. Give it a try! https://www.fab.com/listings/df37eb46-09bf-4604-9307-cdc39c769790 https://dev.epicgames.com/community/learning/tutorials/eGME/unreal-engine-animgen14 Aug 2026 14:32 +0000at://did:plc:ay6paf5o7pabd44vfgmzltcl/app.bsky.feed.post/3mt2esaad5k2ihttps://bsky.app/profile/theorangeduck.bsky.social/post/3mrummtwn2k2sOne of my most requested articles is something on inverse kinematics and foot sliding. I finally found the time to write up the little recipes that have served me well through the years, including an offline method I used recently that works surprisingly nicely. https://theorangeduck.com/page/inverse-kinematics-foot-locking30 Jul 2026 14:11 +0000at://did:plc:ay6paf5o7pabd44vfgmzltcl/app.bsky.feed.post/3mrummtwn2k2shttps://bsky.app/profile/theorangeduck.bsky.social/post/3mlgnpm2jek2uI'm just going to go out and say it - respectable people don't litter. https://theorangeduck.com/page/respectable-people-dont-litter09 May 2026 16:22 +0000at://did:plc:ay6paf5o7pabd44vfgmzltcl/app.bsky.feed.post/3mlgnpm2jek2uhttps://bsky.app/profile/theorangeduck.bsky.social/post/3mhqel776tk26Here's a write-up of my investigations into a technique called "Inertial Easing" - an interesting idea on how to use easing functions for spring-damper-like applications. https://theorangeduck.com/page/inertial-easing23 Mar 2026 15:24 +0000at://did:plc:ay6paf5o7pabd44vfgmzltcl/app.bsky.feed.post/3mhqel776tk26https://bsky.app/profile/theorangeduck.bsky.social/post/3mewgt5piic2jRecently I've been taking another look at fitting movement model parameters from data and managed to derive some formulations that work in terms of starting and stopping times and distances - something that is potentially a lot more intuitive for designers to use. https://theorangeduck.com/page/fitting-code-driven-displacement-revisited15 Feb 2026 21:05 +0000at://did:plc:ay6paf5o7pabd44vfgmzltcl/app.bsky.feed.post/3mewgt5piic2jhttps://bsky.app/profile/theorangeduck.bsky.social/post/3mduyg6mua22wA reader found a bug in the code listings on my "New Movement Model" article. The intermediate spring should take "track_vel" as a target, not "next_vel" (see https://github.com/orangeduck/MovementModel/blob/main/movement.cpp#L451) article has been updated!02 Feb 2026 13:49 +0000at://did:plc:ay6paf5o7pabd44vfgmzltcl/app.bsky.feed.post/3mduyg6mua22whttps://bsky.app/profile/theorangeduck.bsky.social/post/3mbtzfhlqgk2oI've prepared a little blog post discussing the ideas behind the new Smooth Walking Mode we developed for UE's Mover plugin. This Movement Mode is also used in the new UE 5.8 GASP release! https://theorangeduck.com/page/new-movement-model07 Jan 2026 17:44 +0000at://did:plc:ay6paf5o7pabd44vfgmzltcl/app.bsky.feed.post/3mbtzfhlqgk2ohttps://bsky.app/profile/theorangeduck.bsky.social/post/3m6fjb2e55k24I'm so happy to finally be able to talk about our new SIGGRAPH Asia paper "Control Operators for Interactive Character Animation". It's been by far the most work I've seen go into a SIGGRAPH paper (thanks goes to @gouruiyu.bsky.social) and a fun project all round. https://theorangeduck.com/page/control-operators-interactive-character-animation24 Nov 2025 19:02 +0000at://did:plc:ay6paf5o7pabd44vfgmzltcl/app.bsky.feed.post/3m6fjb2e55k24https://bsky.app/profile/theorangeduck.bsky.social/post/3m4436v5ck225Time for another short story :) https://theorangeduck.com/page/review-silver-canyon-connector-trail26 Oct 2025 14:06 +0000at://did:plc:ay6paf5o7pabd44vfgmzltcl/app.bsky.feed.post/3m4436v5ck225https://bsky.app/profile/theorangeduck.bsky.social/post/3m2m467lcck2cThis year I had the chance to visit the Peace Museum in Hiroshima. Of all the things I saw in Japan this is the place that will stay with me forever. theorangeduck.com/page/hiroshima https://theorangeduck.com/page/hiroshima07 Oct 2025 12:16 +0000at://did:plc:ay6paf5o7pabd44vfgmzltcl/app.bsky.feed.post/3m2m467lcck2chttps://bsky.app/profile/theorangeduck.bsky.social/post/3lyyjxpv2a227With a bit of help from the authors I've added another huge high quality dataset to my Geno retargetings. This time the very nice InterAct dataset (hku-cg.github.io/interact/). You can find it here: https://github.com/orangeduck/interact-retarget/17 Sep 2025 00:04 +0000at://did:plc:ay6paf5o7pabd44vfgmzltcl/app.bsky.feed.post/3lyyjxpv2a227https://bsky.app/profile/theorangeduck.bsky.social/post/3lx5lto7ccc2oMy latest article is on the problem of joint-error propagation - and some techniques for tackling it when doing Machine Learning or other data-driven numerical methods. https://theorangeduck.com/page/joint-error-propagation24 Aug 2025 13:31 +0000at://did:plc:ay6paf5o7pabd44vfgmzltcl/app.bsky.feed.post/3lx5lto7ccc2ohttps://bsky.app/profile/theorangeduck.bsky.social/post/3lwqvcmy5b22uI've just pushed up a version of my GenoView project but implemented in Python (using raylib bindings). Hopefully that is useful to anyone doing ML research building interactive animation systems who wants to make use of PyTorch, Numpy, etc. github.com/orangeduck/GenoViewPython https://github.com/orangeduck/GenoViewPython19 Aug 2025 12:15 +0000at://did:plc:ay6paf5o7pabd44vfgmzltcl/app.bsky.feed.post/3lwqvcmy5b22uhttps://bsky.app/profile/theorangeduck.bsky.social/post/3lsm5ybfdus2nWe have a rare opening on our team for an Animation Programmer. If working with us on shipping Machine Learning animation tech inside UE appeals to you, please go ahead and apply! https://www.epicgames.com/site/en-US/careers/jobs/552733900427 Jun 2025 17:27 +0000at://did:plc:ay6paf5o7pabd44vfgmzltcl/app.bsky.feed.post/3lsm5ybfdus2nhttps://bsky.app/profile/theorangeduck.bsky.social/post/3lrvapjavks2gI've added an appendix to my page on debug drawing text with lines with a contribution from @mikkomononen.bsky.social and his version of a non-monospaced font based on the Hershey Fonts Simplex characters: http://theorangeduck.com/page/debug-draw-text-lines#simplesimplex18 Jun 2025 14:44 +0000at://did:plc:ay6paf5o7pabd44vfgmzltcl/app.bsky.feed.post/3lrvapjavks2ghttps://bsky.app/profile/theorangeduck.bsky.social/post/3lrlxmfojgk2vThere may not be many obvious alternatives, but CLIP is not a great embedding for describing motion. It's trained on static images so has a confused concept of time/tense/ordering, will often focus on the object rather than the action, and usually interprets verbs as nouns:14 Jun 2025 22:07 +0000at://did:plc:ay6paf5o7pabd44vfgmzltcl/app.bsky.feed.post/3lrlxmfojgk2vhttps://bsky.app/profile/theorangeduck.bsky.social/post/3lmddr6bte22uMore than once I've wanted to debug draw text in a game scene but found it not as easy as expected. I made a lookup table that allows you to draw text via line segments. It was a fun little weekend project, even if I'm sure it's something people have done before! https://theorangeduck.com/page/debug-draw-text-lines08 Apr 2025 20:45 +0000at://did:plc:ay6paf5o7pabd44vfgmzltcl/app.bsky.feed.post/3lmddr6bte22uhttps://bsky.app/profile/theorangeduck.bsky.social/post/3llypuonyns2fTime for another long blog post... and today it's all about how we handle the temporal aspect of animation data. And more specifically, how to approach things from a signal processing perspective, covering up-sampling, down-sampling, and everything in-between. http://theorangeduck.com/page/filtering-convolutions-quaternions04 Apr 2025 15:22 +0000at://did:plc:ay6paf5o7pabd44vfgmzltcl/app.bsky.feed.post/3llypuonyns2fhttps://bsky.app/profile/theorangeduck.bsky.social/post/3ljdjghqmws2kJérôme Eippers' YouTube channel is quickly becoming a goldmine for Animation Programming. He is covering so many classic animation papers - reviving a lot of great ideas and techniques that are either under-utilized or forgotten by the industry. https://www.youtube.com/@JeromeEippers/videos01 Mar 2025 18:11 +0000at://did:plc:ay6paf5o7pabd44vfgmzltcl/app.bsky.feed.post/3ljdjghqmws2khttps://bsky.app/profile/theorangeduck.bsky.social/post/3lixpjokvic2pLearned a new spring fact from my colleague @rat-face.bsky.social recently. For a critically damped spring tracking a target moving at a constant velocity, the amount of time the spring will lag behind the target is given by "halflife / ln(2)". Added to my blog post https://theorangeduck.com/page/spring-roll-call#timedspring25 Feb 2025 01:28 +0000at://did:plc:ay6paf5o7pabd44vfgmzltcl/app.bsky.feed.post/3lixpjokvic2phttps://bsky.app/profile/theorangeduck.bsky.social/post/3lgj2wkhonk2yI've uploaded a retargeted version of the 100STYLE dataset matching the other datasets: https://github.com/orangeduck/100style-retarget/ I wasn't sure if I should add it at first. The quality is lower due to the inertial capture, and it's missing finger motion, but overall I figured it's still worth it.24 Jan 2025 18:52 +0000at://did:plc:ay6paf5o7pabd44vfgmzltcl/app.bsky.feed.post/3lgj2wkhonk2yhttps://bsky.app/profile/theorangeduck.bsky.social/post/3lehd5dog6k2sIt's been a while since I did a pure Machine Learning article on my blog, but today I have a post for you about adding noise to Neural Networks, and some fun experiments with Flow-Matching: https://theorangeduck.com/page/noise-neural-networks-flow-matching29 Dec 2024 15:23 +0000at://did:plc:ay6paf5o7pabd44vfgmzltcl/app.bsky.feed.post/3lehd5dog6k2shttps://bsky.app/profile/theorangeduck.bsky.social/post/3lbmvw22pec23My latest article is about one of my favorite techniques in graphics - Müller's method of Polar Decomposition. It also details some variations, including one which is ~2x faster to compute with more regular convergence. https://theorangeduck.com/page/variations-muller23 Nov 2024 16:26 +0000at://did:plc:ay6paf5o7pabd44vfgmzltcl/app.bsky.feed.post/3lbmvw22pec23