I spent the last 3.5 years building a real-time 3D physics engine for sound

As the title says, I've spent the last 3.5 years working on Anukari, a 3D physics simulation much like a video game engine, except that instead of running at 60 steps per second, it runs at 48,000 (or more) steps per second, so that the physics systems can vibrate at audio frequencies. It's commercial software; primarily I am selling it to musicians and sound designers to use for music, sound effects design in film. But also it's pretty fun for non-musical people who just like building weird physics stuff. The main website is https://anukari.com .

I'm a bit terrified to post this here in r/Physics, as I am far more of a software engineer than a physicist. I know enough math to be dangerous, and I once attempted to go to school for physics but they kicked me out when I stopped going to class, so… Thankfully spring-mass physics are pretty simple (although keeping the simulator stable under large time steps has been challenging).

A huge amount of the work so far has been practical details like getting the simulation to run efficiently in real time for hundreds (up to a thousand) of masses, making the GUI for constructing the mass-spring systems easy to use, stuff like that. But now that the product is completely usable, I look forward to adding more physics features. I have plans to add various new simulation parameters for the springs, including nonlinearity, ropes, contacts, stuff like that. Randomness is often useful for sound design, so I've been prototyping parameters for simulating random perturbations in e.g. the velocity of the masses.

Longer-term, I think simulating the vibration of continuous materials using the Material Point Method (as described by Alexey Stomakhin) could be a super intriguing direction to go: https://alexey.stomakhin.com/research/mpm.html

Anyway, I thought folks here may find this interesting. It's a fun introduction to basic physics for people who use it; I have seen a number of kids interact with it and my favorite thing is when people have that "aha" moment where they recognize what the spring is doing, and why a mass is flailing about wildly. 🙂