Verlet Integration and Cloth Physics Simulation (2022)
7 comments
·June 20, 2025pixelpoet
debugnik
Most gamedevs haven't really researched numerical integration, they've just heard that the naive method, which is very often hand rolled outside of physics engines, is Euler; and that particle simulations should use Verlet because reasons. (The inner reason being that the first Hitman game used Verlet and they published a paper about it.)
atan2
Writing that programmers that use Euler instead of RK4 are "bloddy idiots" might work well to get some laughs in a blog post when the author is trying to stress how RK4 is more accurate and stable than the alternative, but there are cases where real-time applications (especially on older machines and older consoles) could not afford the overhead of RK4 and Euler was gave good-enough for what they needed.
Y_Y
Forward Euler is very terrible and can give you wildly wrong answers after just a few steps. If you think higher Runge-Kutta and fancy methods are too complex/expensive you do have cheap and stable options, like implicit euler or leapfrog. It's very likely that your numeric integrator is going to be a hot part of your game loop, it's worth doing ten minutes of research, IMHO.
atemerev
Using irregular timesteps _might_ not be a bad idea if you know what you are doing (but probably not for the usual kinematic simulations). See Dynamic Monte Carlo, Gillespie algorithm, First Reaction method etc (these are mostly the same thing).
rahkiin
(2022)
null
The article says that Euler integration is commonly used in games, and I'm not sure that's true; it's been popularised in gamedev since many years that, and I quote, "if you use Euler integration, then you're a bloody idiot"[0].
BTW the same article series points out that using irregular timesteps is also a bad idea.
[0] Since gone offline, and without the famous quote, but there's an archived copy here: https://vodacek.zvb.cz/archiv/680.html