Pen Plotter Art and Algorithms, Part 1 (2017) | Hacker News Reader

Pen Plotter Art and Algorithms, Part 1 (2017)

mattdesl.svbtle.com

75 pointsTomte25 comments

It is pretty easy to use a 3d printer as a pen plotter. You can easily print a pen holder that mounts to your print head. This one (https://www.thingiverse.com/thing:3139205) includes a retaining screw for different sized pens. I have also seen mods for CNCs that will click retractable sharpies and then use them for layout or part marking. Here is one example: https://www.youtube.com/watch?v=c3LhK2SAusk

As a side note, the MUJI gel pen from the 3rd image (Tesselations, August 2017) are amazing.

I have an Ender 3 (one of the cheapest available consumer 3D printers) and have had success using Inkscape to generate gcode for it. For anyone interested, Processing/p5.js are great tools for programmatically generating .svgs for plotting. It’s great fun! Thinking about making some wall art soon.

I also have a MUJI notebook on my desk that I use to sketch out ideas before coding them :)

I've heard that if you're using different-sized pens on the same print, it can be better to wrap them in tape to fit, to avoid alignment issues.

I had some issues with my g code files on my prusa printer - I think it expects some special start up sequence of g code. There is also an x y z offset which seemed useful, but it replaced my calibration so I needed to recalibrate after!

one issue is that pens need to have some compliance to the surface (versus a 3d printer or CNC, which don't)

to get good lines on my CNC machine, I had to make a slide on the z axis with a spring to apply force downward with the pen.

Discussed at the time:

Pen Plotter Art and Algorithms - https://news.ycombinator.com/item?id=16043159 - Dec 2017 (12 comments)

One of the cooler pieces of plotter art I've seen was logging the memory state of every byte over time for the playing of a NES game for a few seconds. An NES only has 2048 bytes of memory, so you can plot sparklines for all of them on a poster pretty readably. https://www.michaelfogleman.com/plotter/#nes

shameless plug, but some friends and I have been working on fountaincards.com, which uses a plotter to write and send cards written with a fountain pen.

Right now we are still getting set up, but it’s been fun to dive into the world of Inkscape and try to figure out how to automatically generate SVG’s that look like a human really wrote them.

I tried to register via Google at https://fountaincards.com/register and received a 404.

Freaky timing. I've been working on a DIY CNC mill on and off for the last couple of years and finally got it all working over the weekend. I've spent a few hours this week playing with processing to see if I can make something cool that I'd like to look at on my wall

pics of the CNC?

It's a bit dusty - https://imgur.com/a/phNC0Xj

We are currently in lockdown here so I have to wait until we move up another level before I can go get my shop vac.

Nice work. Do you have any trouble with the dust gathering in the timing belt?

No but I’d say I will eventually. I’ve been giving it a quick brush and a blast with the air compressor. Haven’t really made anything major with it yet

Are you me? I had the same reaction. I've finished mine last weekend, but haven't had time to start with the actual art part of it. Perfect timing

Only tangentially related to this post, but does anyone know what sort of algorithm I would use to create pen plots from photos, something like this?

https://twitter.com/PhotoPuck/status/1412540641066749953

The basic algorithm is some sort of halftoning I guess, but I'm impressed by the way the lines follow the contours of the objects in the scene, they're not just random squiggles trying to reach a certain darkness. So if there's an object with obviously vertical lines, it'll be drawn by the plotter using vertical lines as well. How might I achieve something similar?

I'm not sure how the curvy shading was done, but the lines following edges looks like the results of vectorising the output of an edge detector: https://en.wikipedia.org/wiki/Edge_detection

Thanks, I'd figured it was something like that. It's very impressive how it works, he has more examples in his feed. Sometimes it looks more like there's a conversion to a sort of "visual direction" in the image which the lines follow, not just edges.

If you follow level curves as well as edges, you can get that visual direction effect. I think people may also do shading in directions similar to nearby edges.

I think coming up with an appropriate stippling algorithm is part of what makes it art; different techniques make different textures. But here's an example that comes with full source and is not too complicated: https://greweb.me/plots/236

And another approach (from the makers of the AxiDraw) that's more dot-like: https://wiki.evilmadscientist.com/StippleGen

Great, thanks for the links!

This doesn’t really answer your question, but I think people interested in this question would like the book Opt Art. It introduces a number of techniques for using constraint solvers to arrange lines such that they look like a source image.

https://press.princeton.edu/books/hardcover/9780691164069/op...

and he's on twitter here: https://twitter.com/baabbaash

If you like plotter art, Anders Hof aka "Inconvergent" does some nice work (and sells plotter prints)

https://img.inconvergent.net/plot/

If you like some of the art others have mentioned in this thread, the very analog and mechanical art by James Gandy might also be of interest:

http://www.jamesnolangandy.com

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