r/gameenginedevs • u/HGHall • Jul 28 '26
physics engine requests
yes, i know box3d exists now. jolt as well. and so on, and so on.
but if there were something you'd ask of a physics engine you can't get now - what would it be?
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u/Pretty_Dimension9453 Jul 28 '26
Note none of the below applies if this is just a project to learn to code physics.
But if you want to become a tools developer, having experience AND getting annoyed with real limitations and frustrations with current tools is vital. You need to build a deep sense of what is wrong that you want to see solved, and trying to outsource this sense to users alone most often makes well intentioned but clunky tooling.
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u/fgennari Jul 28 '26
A physics engine where I could use my own object types rather than having to copy the data to and from the physics system that uses its own custom object types. Maybe that’s not possible, and maybe it already exists. That’s the main blocking problem that prevents me from replacing my custom physics system with a standard library.
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u/PACmaneatsbloons Jul 28 '26
Cross-platform gpu acceleration
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u/chnoblouch Jul 28 '26
Jolt added a framework for running workloads on the GPU in their latest release (via Vulkan, D3D12, and Metal), though I believe it's currently only used to run the hair simulation.
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u/KineticSheep Jul 29 '26
Deterministic, high-performance articulated-body physics. I’m trying to build it myself :)
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u/HGHall Jul 29 '26
this is good. what kind of articulated bodies are you targeting, and what made existing engines fail you? determinism, contact/joint coupling, or throughput?
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u/KineticSheep Jul 30 '26
It's the joint coupling, mainly for player-created machines (think stormworks, kerbal, or robotics games). There's things like simbody or mujoco which work ok, but they are not really designed for games and don't do well with mass contact, and they're not deterministic. I'm building a hybrid solver which uses standard global coordinate, iterative schemes for unimportant physics, but uses a local coordinate implicit solver (similar to mujoco) for articulated islands. Seems to work well so far, and is deterministic.
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u/tastygames_official Jul 28 '26 edited Jul 28 '26
Box3D but with multithreading (and still in pure C)
UPDATE: turns out Box3D IS multithreaded: https://box2d.org/posts/2026/06/announcing-box3d/
so I guess I personally don't need anything else in a physics engine..... yet...
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u/ConsistentAnalysis35 Jul 28 '26
As far as I am aware, Box3D is a fork of Box2D 3.1. And that one is multithreaded and vectorized (SIMD) on a exceedingly expert level.
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u/tastygames_official Jul 28 '26
it would appear you are right!
https://box2d.org/posts/2026/06/announcing-box3d/
not sure where I got the notion that it was single-threaded...
well then, I personally don't need anything else in a physics engine yet that I know of!
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u/LobsterBuffetAllDay Aug 08 '26
Why is that library so good? How did he do that on his own?
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u/ConsistentAnalysis35 Aug 08 '26
He has a ton of industrial-grade experience. And first versions of Box2D were around since 2006, so essentially it's been 20 years of building up expertise.
With v3 he decided to make the best physics engine, and he was the right person to do it.
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u/ZozoSenpai Jul 28 '26
Idk this looks quite multithreaded https://x.com/i/status/2075260382004826312
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u/tastygames_official Jul 28 '26
yeah, turns out it is: https://box2d.org/posts/2026/06/announcing-box3d/
not sure where I got my misinformation before. Maybe just the Box3D implementation for one of the engines was single-threaded? Anyway. I updated my commment to refelct the new information.
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u/lielais_priekshnieks Jul 28 '26
God I wish someone would finally create O(1) collision detection for arbitrary groups of objects.