Vehicle Physics

[latent bison]

Hey everyone,
I’ve been working on a fully custom vehicle physics system in Unreal Engine: wheel colliders, suspension, drivetrain, differentials, custom friction model, and a prediction-based substepping setup. It’s all built from scratch in C++, no Chaos vehicle stuff involved.

I put together a quick video showing the current behavior. I’m thinking about releasing the whole system as open source, mainly because it might help other devs who are fighting with the same problems.

If you get a minute, I’d really like to hear how this feels from your perspective.
Would this be useful for your own projects? Anything you’d want to see expanded or documented? Or does the idea of having this open-source actually sound exciting to you?

I’m still deciding what the licensing model will be. It might be free, or there might be some restrictions depending on use cases.

I also want to know your feedback on chaos vehicles, as I have not touched it in a year. I do not know how advanced and reliable that is, and if anyone has succeeded in using it functionally!

Appreciate any feedback.

https://youtu.be/2PlRtI2_xE0

[weak knoll]

Surely useful. I was never able to use Chaos cars in a meaningful way, mostly since the functionality is not well documented. I ended up with Fgear, mostly because documented and excellent support. Hear people say similar about R-Tune. Another option is welcome but make sure there are examples and documentation understandable for people not having deep vehicle physics knowledge.

[steady stirrup]

Well ppl do love to hate chaos vehicles, i dont blame them.
Ppl just want explanations, documentation, ability to tinker with things, set configs, its limited in that in ways, and ppl do hate skeletal meshes and the setup.

Chaos vehicles is kinda in odd spot, if u can deal with it and override it yourself, that means you already know c++, but in that case u can just roll your own vehicle physics, if not, then u need to tinker with it and make something usable in bp, its possible, but needs time.

So regardless this project, dont really know whats the best course of action, more is better i guess, more competition wont hurt, paid or free i guess.

But if u want ppl to love it, document it and if it is c++ based, add as much possibility to override and config things in BPs as possible, oh, and dont use skeletal meshes 😆

[latent bison]

I do have skeletal mesh as my base, what is so wrong with it that you do not like? 😅 I find creating a physics asset for the car to be a good choice. But I can add the option to change it to just an skeletal mesh as well

[steady stirrup]

its not that i dont like it, many ppl seem to not like it, setup is harder, its less known topic, needs bones, constraints, physics shapes etc. not sure
i think modular setup is what ppl would like to have without all of the hated skm workflow and issues, its just more flexible and universal
if u can make it both ways, then its even better

i think that skm is used for more, lets call it, classic vehicle setup for games, when u have just racing cars that wont be modified much, u choose a car, colors, maybe some parts and thats it, and if u unlock new things its mostly complete new cars to use, liveries etc. thats how most racing games work, so there is no need for more modularity

but if u want something different, more customizable, might not be ideal

[latent bison]

Awesome, thank you for your feedback. Never heard about FGear! I have tried R-tune it was just very entry level

[latent bison]

Got it, thanks for the feedback. I will try to add support for it in future hopefully before releasing it publicly!

[native drift]

this looks great!

[latent bison]

Hey everyone 👋

I just released my VehiclePhysics plugin for Unreal Engine.

It includes custom wheel colliders, tire force modeling, and drivetrain simulation. Built for video games and interactive simulations that need more control over vehicle behavior.

Available for non-commercial academic/educational use.

GitHub: https://github.com/Kouroshx99/VehiclePhysics
Project page: https://kouroshafsharpour.com/custom-car-physics/

[native drift]

wow cool stuff!

[latent bison]

Small update to the VehiclePhysics plugin:

Added open, locked, and LS differential types.

Makes drivetrain behavior a lot more realistic under uneven traction.