That is really, really cool! I'm not but I look forwards to hearing more about it in the future. Really curious about how you move the brush. Pointillism? Filling polygonal regions with lines? Some sort of interesting "imitate real brushwork" algorithm?

Do you do color change by swishing the brush in water? Ooo, does it mix colors? Because that'd be super fun if probably impractical.

I take a bunch of different approaches so the short answer is "Yes" but I'll try get a little more in depth.

I mostly use something akin to a "imitate real brushwork" algorithm, but it's more a "mess with the code until it looks right to me" algorithm.

> Do you do color change by swishing the brush in water?

Sort of, this aspect of definitely has some physical bugs (flooding my work area occasionally) but I am using an automated water pot that works using a pythagorean siphon and is controlled using the coolant flood commands in GRBL (used to cool bits when cutting with a CNC ordinarily)

> Ooo, does it mix colors?

This is what I'm currently working on, but it's very much a non-trivial thing to solve. Luckily you don't have to be precise to make good art, there's a lot of opportunity for happy accidents.

self promo: While I haven't been very good at producing compelling media about my plotter, I do have a patreon where for $7/mo I mail you a postcard-sized plot every month demonstrating whatever thing I'm working on at the moment. https://www.patreon.com/thot_experiment

here are a few examples of last month's plots, these are colored by hand https://thiic.cc/heavy/bb_plot.jpg https://thiic.cc/heavy/crank_plot.jpg https://thiic.cc/heavy/pedal_plot.jpg

and here's a few that are pure robot https://thiic.cc/heavy/abstract_plot.jpg https://thiic.cc/heavy/other_plots.jpg

Really cool! Thanks for sharing.

Here is a simple commercial product (designed by EMS who also makes the axidraw plotter) https://watercolorbot.com/

I'll look for you!