Particle-driven liquid simulation + RBDs, all in Cinema 4D, using force modifiers to generate the swirling motion. Rendered in Redshift. Happy to answer questions about this here. Also feel free to follow me if you like this kind of stuff.

Hi everyone, I wanted to share an open-source physics and math engine I’ve been working on, called FluxRender.

My goal was to bridge complex mathematical definitions with real-time, interactive visual analysis. Under the hood, it uses Taichi for GPU execution and includes a built-in Lattice Boltzmann (D2Q9) fluid solver.

I designed the architecture to be completely modular—every component is independent and customizable. Despite this flexibility, the default settings ensure ease of use. You only need about 10 lines of Python to visualize a custom vector field, or ~20 lines to set up a full CFD simulation.

It’s also fully interactive right out of the box: you can freely navigate the 2D space with the camera, attach custom UI buttons to tweak physics on the fly, or use cursor regions to dynamically spawn particles with your mouse.

You can install it via PyPI:
pip install FluxRender

The code, docs, and more examples are on my GitHub. I'd love to hear your feedback on the architecture or the rendering approach!

GitHub: https://github.com/TodorokiBoy/FluxRender

Docs: https://todorokiboy.github.io/FluxRender/

I've been running a living world for a while now: ten thousand souls, hundreds of settlements, weather, harvests, families, feuds. You can watch it live here: world.world-sim.uk

For the past few weeks I've been rebuilding how you see it. Same world, very different eyes. The image is a sneak peek.

It lands in the next few weeks.

The solver is based on the Wētā FX paper (Guided Two-Way Coupled Bubbles + explicit SPH + manifold advection). The underwater bubble system features a locally resimulated fluid with two-way coupling to the bubbles. The foam is handled via an SPH simulation projected onto a 2D manifold of the water surface. The solver implements standard SPH forces such as viscosity (mu), cohesion (C for strength, beta_c for radius), and surface friction against the water. The original authors apply a particle volume multiplier to the cohesion force. While this is valid and supported as an option in my solver, I prefer using the neighbor's volume multiplier instead of the active particle's volume. To my eye, this yields visually superior foam clustering.

The foam is constrained to the surface via manifold advection: forces are decomposed into tangential and normal components, the normal component is discarded, and particles are projected back onto the water surface using Newton iterations.

Hey everyone,

I built an interactive web based universe simulator with over 150 million catalogged stars, already over 2000 unique visitors!

Top left: velocity. Top right: vorticity
Bottom left: velocity mag. Bottom right: density

Simulation:
grid: 200x200
top wall velocity: CFL 0.45, water wave speed: CFL 0.09 (at starting density)
effective Re: approximately 100k
pressure function: shallow water

Link: https://nohope.io

There is something very satisfying about controlling a swarm/flock like this. Curious what people think!

I’m a computational drug discovery researcher, and I thought this community might appreciate seeing an actual molecular dynamics simulation!
This is a 100-nanosecond simulation I ran of semaglutide (the active ingredient in Ozempic) bound to the GLP-1 receptor.
The simulation models how the drug and receptor move, flex, and interact at the atomic level over time. Unlike a static crystal structure, molecular dynamics lets us explore how these molecules behave in motion.
100 nanoseconds might sound incredibly short, but that’s a substantial amount of simulated time when you’re calculating the motion of thousands of atoms!
This visualization comes directly from my molecular dynamics trajectory, not an AI-generated animation. Enjoy!

Hi Guys,

made a free browser game where you are truck and you have 4 legs.

Mostly IK/FK and solvers.

https://igoryakunin.itch.io/truck-on-legs

By simulating light as a Cellular Automata, one can render some objects. This is two spheres shone through a lense into a camera (With a light behind them)

My kids and I are creating some of these simulations on our youtube channel Orbodrome

V.1.5

A game I always wanted to code now done with the help of Claude 5.5. Should I put more work into this?

The "real" physics was too heavy to simulate many players but the visual uses the "real" physics of balls kept upright by an inner volume and moving from only contraction between surface vertices and an additional inner weight. I think it came out cute.

Some tuning is still needed. The "king" has too little to fear although it loses mass from moving alone and can lose to a portal but I think it's still too fast.

This instance supports 400 players across 4 planets but I can get a server for 5000 across 10 worlds, too.

[https://blob.nostr.info/\](https://blob.nostr.info/)

XPBD cloth sim with forces coming from real-time monocular depth.

Pressure Works is out now on Steam!

Build machines out of real pneumatics: hose up air supplies, valves and cylinders, then hit Test and watch your contraption push, lift, spin and fling actual physics objects.

Sandbox: beams, gears, wheels, motors, balloons and propellers. Build whatever you can imagine. Even computers!
Puzzles: get the ball into the goal, from a simple push to machines that run themselves.
Time trials: build a vehicle, climb in, and race the clock.
Leaderboards: fewest parts and fastest times, ranked worldwide.

No tutorial, just tinkering. When you get stuck, the built-in Engineer's Handbook has the recipes.

https://store.steampowered.com/app/5133090/Pressure_Works/

XPBD softbody simulation in POPs using Gauss-Seidel @ 60fps and 70 shader passes (can't do substepping in same shader pass)

When TouchDesigner introduced POPs one of the first things I tried making was an xpbd soft-body sim, and it looked like this and this. Since then, I've rewritten it multiple times and watched ten minute-physics' tutorials over and over. Many simulation explosions later, it turned out that my very first solver was (mostly) correct, but I was colouring the graph and building the tet constraints in the wrong way..

Edit:

Resources:

Ten Minute Physics

Eric Arnebäck's blog

Vivace

XPBD paper + earlier PBD paper from Macklin

I implemented Surface Turbulence as a proof of concept Houdini plugin for a project with Stormborn Studios. It adds small surface waves without rerunning the base liquid simulation.

The clip shows the before/after comparison, surface tracking and wave simulation.

I made a full video explaining the method and math, with a tool demonstration and benchmarks:

https://youtu.be/l5jDmvfzql0

Based on Surface Turbulence for Particle-Based Liquid Simulations

You guys really liked my post 2Y ago early on in the project (https://www.reddit.com/r/Simulated/comments/1j81ca9/power_network_tycoon_a_physically_accurate_power/) but TODAY I've released the final product after a little over 4 years of solo development.

I’m a power engineer and started making it as a hobby project around the kind of power system problems I find interesting. It’s a physics-based power grid simulation covering generation, renewables, grid stability, thermals, extreme weather and more.

Available now on PC, Mac and Linux/Steam Deck

Steam: https://store.steampowered.com/app/2429930/Power_Network_Tycoon/

Trailer: https://youtu.be/wrLPvUqbzu8

Detailed video I think you simulation guys will like: https://youtu.be/QAWecGI0Im4