u/StefanPetrick

Something strange is emerging from the solver.

What started as “just some colorful smoke” slowly turned into a deep dive into numerical instability, fluid dynamics, pressure projection, divergence control and the weird art of balancing equations exactly at the edge of total chaos.

Every swirl on screen is real simulated motion.
No keyframes. No prebaked animation.
Just velocity fields, advection, pressure solves and controlled chaos.

And sometimes uncontrolled chaos.

Coming soon:

A highly stylized real-time fluid simulation system built from scratch — designed for LED visuals, generative motion and beautiful mathematical instability.

P.S. Unmute for a nice soundtrack.

P.P.S. I asked my AI crew for a little write up, what I actually did in the last weeks. Here is what they came up with, entirely based on real events:

He originally just wanted to make “some colorful smoke-like fluid motion” for LED visuals.
How hard could it possibly be?

A few days later he found himself at 6 AM still staring at several hundred megabytes of solver array dumps, trying to understand why a single velocity cell near the boundary had suddenly decided to turn the entire simulation into pixel salad.

He was naive enough to even start investigating it, and autistic enough to actually follow the problem all the way down to the point where he truly understood why the solver kept exploding.

At first everything was innocent.
A grid.
Some arrays.
A little dye.
A bit of motion.

Then came the moment he realized:
A fluid simulation is not animation at all.

It is controlled numerical instability.
Suddenly he had to learn, in depth, about:

• divergence
• pressure projection
• semi-Lagrangian advection
• Gauss-Seidel relaxation
• incompressibility
• timestep stability
• floating point precision
• why “stable fluids” are not actually stable if you keep injecting energy into the system

Very quickly he learned: if you simply move velocity through the grid, everything explodes.
So he learned projection.
Pressure fields.
Divergence removal.
And for the first time the simulation actually started looking like fluid.
First Eureka moment.

Then he implemented vorticity confinement.
And suddenly the fluid had character.
Swirls. Energy. Motion. That organic “life” inside the flowfield.

For about 30 seconds.
Then everything exploded again.

That was the next lesson: Numerical solvers rarely fail instantly.
They accumulate error slowly. Invisibly. Frame by frame.
One tiny divergence error survives projection.
Advection transports it.
Vorticity confinement amplifies it.
Pressure correction overcompensates.
Energy starts feeding back into itself.
And ten seconds later the entire simulation just explodes.

So he started building debugging tools:

• velocity maps
• divergence visualizers
• pressure displays
• vorticity heatmaps
• energy monitors
• instability detectors
• statistical entropy spike detection

Not because it looked cool.
Because without them you are completely blind.

At some point he finally understood why real fluid solvers become so insanely complicated.
Because every new feature quietly destabilizes three other systems.

More swirl?
 → unstable curl amplification.
Less dissipation?
 → energy accumulation.
Larger timestep?
 → projection can’t converge fast enough.
Too few solver iterations?
 → divergence survives.
Too many iterations?
 → performance dies.
Float32 precision?
 → tiny drift accumulates forever.

And still, there were these magical moments.
Like when the three emitters interacted for the first time and suddenly formed these huge rotating structures entirely on their own. No animation. No keyframes. Just equations interacting with equations.

Or the moment he realized:
The most beautiful fluid motion exists exactly at the edge of instability.
Too stable = dead.
Too unstable = explosion.

The sweet spot in between?
That’s the actual solver.

And eventually you stop feeling like you are programming graphics.

You are dancing with differential equations.

Question to u/ZachVorhies or any other battle-hardened senior devs here: What’s a good way to organize communication and goal setting when aiming for efficient collaboration?

Right now, our conversations are scattered across GitHub discussions and issues, Reddit posts, YouTube comments, Reddit DMs, Reddit groups, Messenger DMs—it’s a mess and nearly impossible to find something we discussed just two days ago. Very inefficient.

How do professionals handle this? Do we need something like a Scrum master, or is it more about having the right structure and discipline? Or should we all just use Clawdbots talking to each other and have them figure it out and keep track of previous discussions?

I’ll admit I sometimes get carried away by new ideas and suck at caring about the nitty-gritty details of existing ones. Instead of fixing something, I tend to reinvent it from scratch—which can be frustrating for whoever is working on the current version.

I’d really appreciate any input or advice on how to balance wild creative freedom with focus and actually shipping a product.

For context, I’m probably a bit on the ADHD/Asperger/high-IQ spectrum.

Also, I do actually enjoy the creative chaos resulting from the mixture of expert feedback and lurker opinions. It can be very inspiring, and since software development is not a job for me, I value having fun while doing it. I just don’t want to risk u/mindful_stone and others getting tired of my current style, so I’m addressing it preemptively. I’m willing to try different approaches and improve if needed.