Renshi Asada

An egg tempera painter(77th Sanki Exhibition, 2025) & graphics engineer.
Researching how to simulate real art materials.

[Renshi Asada @renshiasada]

I'm building a multi-platform, real-time paint simulator based on Rust + WebGPU.

I'm strongly interested in how close computer simulation can get to traditional art materials, or in the interrelationship between traditional art materials and digital painting.

Currently, I've implemented basic art materials such as watercolor, oil paint, gold leaf, crayon, and pastel.

You can easily try it out from your browser!
Please give it a try if you'd like.
https://t.co/x5EMm6WXHY

#WebGPU #rustlang

[Renshi Asada @renshiasada]

Started on a simulator for robots that paint. It'll improve mignon's engine and brushes too, so... allowed, right?

[Renshi Asada @renshiasada]

@derfcz @dangreenheck Implicit! Really nice.

[Renshi Asada @renshiasada]

procrastination over. back to work

[Renshi Asada @renshiasada]

A Jumper crab wandering around a city. The renderer from mignon got extended to a wider 3D space. Physics is MuJoCo. Just for fun.

[Renshi Asada @renshiasada]

Very Cool!

[Three.js @threejs]

🦾 https://t.co/ZYYv6CzETS

[Renshi Asada @renshiasada]

For a change of pace after the release: I learned ONNX and MuJoCo Wasm, so I want to hook the engine up to a robot sim.

[Renshi Asada @renshiasada]

finally got a good charcoal simulation result. phew. time to get the release ready.

[Renshi Asada @renshiasada]

Charcoal now has a 3D model, so drawing feels more real.

With real charcoal I keep brushing the dust with my hand, so I'm making the dust movable. Draw over it again and it looks much closer to the real thing.

[Renshi Asada @renshiasada]

@dhvanil Cool! Maybe a wet palette or a retarder? Or have the arm mist the palette now and then, like a person adding water.

[Renshi Asada @renshiasada]

New brush palette, with an animated 3D preview that follows the brush settings. Performance has steadied too, so the release isn't far off.

[Renshi Asada @renshiasada]

@dhvanil Would love to see your robot arm have a go at it 👍

[Renshi Asada @renshiasada]

@dhvanil Planning to. Egg tempera first, then gouache.
That should make opaque vs. semi-opaque properly distinct.

[Renshi Asada @renshiasada]

Updating my site turned into a bunch of rendering and fluid-sim experiments.

The moiré from the advection looks a bit AI, but the whole thing is ~15 KB of plain WebGPU.

[Renshi Asada @renshiasada]

@madmanstudioio Agreed. Speed really does shape how drawing feels. Thanks!

[Renshi Asada @renshiasada]

I tried charcoal drawing on a range of devices, and it needs to be a bit faster. It adds a lot to what you can draw, so I'm going to work on speeding it up.

[Renshi Asada @renshiasada]

@dhvanil Looking awesome!

[Renshi Asada @renshiasada]

mignon Pro for Android and iOS mostly looks the way I want it to now.

Next I'm adding PSD export, more digital pen features, and animation.

Would be nice to get it all done in November.

[Renshi Asada @renshiasada]

Mignon Sketch v1.10.0 released!
https://t.co/vITPlL79Dg
https://t.co/ADiBbARopt

[Renshi Asada @renshiasada]

Had no idea how this would turn out, but it's starting to take shape. Tuning friction and static should get it further.

Glad I could put an MPM engine in here: it's the base for running liquid through it, dissolving pigment in water, and using viscosity to make the oil paint richer.

I can add salt too. More range, and now the media have a common ground to act on each other, which I like.

Speed is fine. Memory is the problem, so that's next.

[Renshi Asada @renshiasada]

Starting on the charcoal brush. No idea if it'll actually work.The plan is to use Mixed MPM to move charcoal particles around and let them settle, so the strokes have some life in them...

If charcoal works out, I want the same powder movement in the pencil.

Either way I'll have to implement fixative too.