# Position Based Dynamics

**URL:** <https://discourse.julialang.org/t/position-based-dynamics/70559>\
**Category:** Modelling & Simulations\
**Created:** [October 28, 2021, 2:51pm UTC](https://discourse.julialang.org/t/position-based-dynamics/70559 "2021-10-28T14:51:35Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![vpuri3](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/vpuri3/32/30292_2.png) [@vpuri3](https://discourse.julialang.org/u/vpuri3)\
**Post date:** [October 28, 2021, 2:51pm UTC](https://discourse.julialang.org/t/position-based-dynamics/70559/1 "2021-10-28T14:51:35Z")

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hi all, I’m new to robotics and was wondering if anybody has thoughts on Position Based Dynamics methods: [https://matthias-research.github.io/pages/publications/smallsteps.pdf](https://matthias-research.github.io/pages/publications/smallsteps.pdf). They seem to be able to account for constraints in a seemingly straightforward way.

if there is interest, I’m willing to prototype these algorithms in RigidBodyDynamics.jl, or start a new project altogether. im really just trying to get started with robotics simulations for kicks. my background is in writing fluid dynamics solvers. thanks in advance for your guidance

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**Author:** ![ChrisRackauckas](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/chrisrackauckas/32/77_2.png) [@ChrisRackauckas](https://discourse.julialang.org/u/ChrisRackauckas)\
**Post date:** [October 29, 2021, 2:22pm UTC](https://discourse.julialang.org/t/position-based-dynamics/70559/2 "2021-10-29T14:22:23Z")

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You might as well just use ModelingToolkit to tear into an ODAEProblem to handle the constraints and use a higher order adaptive solver which reuses Jacobians. That would be the same generalization to these techniques that Dymola uses, which would probably be a good order or two magnitudes faster than any 1st order technique (if you need more than minimal accuracy, if the events are not too too close, etc.).

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**Author:** ![Firesand](https://avatars.discourse-cdn.com/v4/letter/f/46a35a/32.png) [@Firesand](https://discourse.julialang.org/u/Firesand)\
**Post date:** [October 29, 2021, 7:55pm UTC](https://discourse.julialang.org/t/position-based-dynamics/70559/3 "2021-10-29T19:55:22Z")

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I would really love to see Position Based Dynamics as a separate Julia library. I’ve been following the work of Müller, Macklin et al. for some time now and am enjoying Müller’s new [Ten Minute Physics](https://matthias-research.github.io/pages/tenMinutePhysics/index.html) on Youtube. I am very new to Julia and am learning it specifically to speed up calculations for some future simulation projects. A new PBD Julia library would be incredibly useful not only for me but many, many others as well. The thing I am still trying to figure out for my simulations is how to best display the 3D output. Having Julia integrated into Blender, the Godot engine or even [Raylib](https://www.raylib.com/) would be simply awesome. Anyway, I for one, fully support your idea to write a Position Based Dynamics library for Julia.

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**Author:** ![scelles](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/scelles/32/220408_2.png) [@scelles](https://discourse.julialang.org/u/scelles)\
**Post date:** [November 18, 2021, 6:42am UTC](https://discourse.julialang.org/t/position-based-dynamics/70559/4 "2021-11-18T06:42:42Z")

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About Raylib and Julia… maybe you should have a look at [Clang vs CBindingGen - #22 by mhinsch](https://discourse.julialang.org/t/clang-vs-cbindinggen/56693/22)  
Pinging @mhinsch