This is very coincidental timing. The physics simulation in the Source game engine, and Garry's mod, absolutely cemented in me an interest in computational phys

This is very coincidental timing. The physics simulation in the Source game engine, and Garry's mod, absolutely cemented in me an interest in computational physics. I really wanted to see fully simulated fluid water in games, particularly GMod, but it never really happened, 15 years ago. This never stopped bothering me, so I recently loaded up the game and programmed an entity that was simply a particle that repelled itself with inverse distance-squared falloff. I was only able to get up to around 100 particles before the game slowed from 200+ fps to ~10. There seemed to be a huge amount of overhead in the lua scripting system's connection to the game/physics engine. Something about getting the position of 100 particles, or asking for all the particles within a given range of each particle, even for only 100, was enough to send frametimes over 100ms-1000ms. I wanted at least 500-1000 particles at at least 10fps, and I'm sure in terms of raw math, that is nothing for modern CPUs, even with the most naive implementation. I had to figure out exactly which lua functions had the most overhead for such a small amount of simple math. So, I re-wrote the script, seeking to chase every rabbit hole that would let me increase the number of particles while maintaining over 10fps. 1. Switch from per-particle loop, to a global loop that cached each particle's position per frame, so it was more pure math and less engine bindings/"context switching". Approx 50 particles to approx 150. 2. Limit the particle simulation to 10hz instead of 66hz+, and adjust the force scale to compensate. Raised the limit to approx 300-400 particles. 3. A dynamic scaling system, so that the system would never try to simulate more than 100 particles at once, per 10hz tick. Raised the limit to approx 700 particles. At this point, there are now other non-CPU bottlenecks. Any method of drawing 700 entities, even basic wireframe?, even with a very high end GPU on a nearly 20 year old game, is significant, and there's no easy way for me to break past this. I am sure if I learned how the source engine's plugin system worked, and I hooked into the physics engine using C++ instead of however the lua bindings work, I should be able to simulate a thousand particles at 100+fps, but that's about where the scope of the project starts to contend with "real life", and I continue to wait for a 3D sandbox game with satisfying fluid physics. Your optimization method of "only one iteration per frame" is in a sense, the same, and in a sense, the opposite of my method of simply not even simulating every particle every frame... I just didn't have the spare performance for that. Then again, I'm only simulating a single force field with no proper collision detection or anything fancy