unfortunately sharpies aren’t very good. i use paint pens but they require significant pressure to open the valve behind the nib.
i am currently working on making my own markers...
It works like old typewriters. You align the corners of the paper and then clamp it.
Compare that, at the time, to the top of line of a Gerber (or 3M) plotter that was the only one able to handle 12+ ft. It used an array of sensors that at runtime adjusted the clamping-wheels pressure to keep the paper/vinyl roll aligned.
It was around $15-18K, while my Ioline was ~$1,300.
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Could you tell me more about your markers?
The "pens" i've made are a piece of delrin, with a 1/4" hole drilled down the middle and a piece of 1/4" F1 felt stuffed in there.
Here's the pen, sorta working https://www.instagram.com/p/COE-5dSpPAm/ and here is a longer drawing. you can see that it does still go from "too much" to "too little" as the line draws. https://www.instagram.com/p/CO4xW6QJLf2/
There are many, many other drawings in that profile. The thin line ones were made on an HP DraftPro DXL.
https://www.instagram.com/p/Byl2M0oJnwJ/
How do you code that? I'm trying to guess who inspired you: Duncan Brinsmead, Keith Peters?
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About the pens, what happened to this brush: https://www.instagram.com/p/CB9iYKiJQ_A/
I'm thinking of a stronger felt, if they exist, with that brush shape.
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Sometimes I use vinyl instead of paper because it's "easy" to clean any drips with q-tips and 90%+ alcohol.
On the brush: That's a chinese calligraphy brush. I spent a bunch of time making a bearing holder to let the brush swivel freely. It didn't work. The brush is very, very hard to get to behave. A human will tilt it slightly in order to get the bristles to go in the right direction, but the CNC machine keeps everything completely orthogonal. Works for pens but not brushes.
Edit: Keith Peters' algorithmic stuff ( http://www.artfromcode.com/ ) does seem to share a lot of the same underlying techniques. Perlin flow fields and hex truchet tiles especially.
