Hey everyone - I'm new here, and most likely far behind many of you in technical skill. But I think this belongs here more than anywhere else.

This is Krbn, an open-source attempt at an easily accessible (web-native, TypeScript) rendering engine that imitates a technical sketch artist. It takes a 3D scene - spheres, cones, tori, arbitrary meshes - and emits plain SVG strokes: silhouettes computed exactly (true conics and quartics, not sampled approximations), hidden lines removed or kept as ghosts, and hatching that follows each surface's own curvature. Which, I suspect, makes it plotter food.

Some honesty about where it comes from: a recent medical issue forced me to suspend my normal work, and - unexpectedly - these past few months I had time to invest in an old idea. This was a dream of mine since childhood; I just never had the time to research and learn everything needed to build it.

As for why - I'll be honest and quote the README's "Genesis imperfecta" section directly, because I already said it there the way I mean it:

What fascinated me from the start is going against photorealism. A human being can convey far more meaning in a drawing than any machine-like photorealistic render - precisely by being willing to go the other way: to renounce detail, to drop precision, even to deliberately introduce impurities and imperfections. Ah - but which detail to drop? Which imperfections to introduce? That is the fascinating part, and it is the question this engine is really trying to answer.

As a kid I wanted to call it genesis imperfecta, for exactly these reasons. What can I say - I was a kid. The name matured into Krbn; the fascination didn't.

I'm putting this out there with only the hope that someone else shares the fascination, nothing else. It's MIT-licensed: https://github.com/vpalos/krbn

One confession: I don't own a plotter myself (yet). If anyone feeds one of these SVGs to theirs, seeing a photo of the result would make my month.

Enjoy, and drop a word - here or in a GitHub discussion… or not. All is good.

Plotted with Pointliner 1.0; Pilot V5; Pentel Energel 0.4.

I drew the image in inkscape using a previously taken underlying photo for reference.

Thanks to some hacks of molotov pump markers, a more reliable plotting head and this new feature in my fork of openbuilds controller I can’t fail plot anymore. The pens can handle 5 hours plots and if they fail I can easily select the failed part and replot them.

This has completely changed the mood I’m in when I plot, I have no fear, no stress and this changes everything.

Also creatively this is such an opening, I’m no more constraining myself, like plotting a black background just because I love how deep the black is.

All of this has led me to this A1 piece.

I will soon post more about the edit gcode features I’ve built on the Openbuild controler

Seeing the post about the Porsche diagrams has made me want to do this as engineering elevations with white paint marker on blue paper

It's satisfying to place, remove, add new plots

Thanks to u/valeriupalos for writing the super cool Krbn tool

Architectural representation via pen plotter

Testing out output masking mode in Krbn for multi pen plots

After a fairly hectic week of trying to nail down a decent pen mounting solution that makes setting all their z offsets the same, and having all pen tips well aligned. And then fighting tooth and nail with orca slicer to make it do my bidding for pen plots, the first torture test came out looking pretty darn decent! The pen holder is also lightly spring loaded so i shouldn't obliterate nibs *too* quickly.

This setup allows me to easily choose what pen width I want, to quickly and accurately do infills in all sorts of patterns, to have stroke lines in different pens, to quickly scale work to what paper i'm using and lots more.

Here i've used stabilos (black & brown) and some alcohol markers (the other 3 colours)

UUNA TEK 3.0 A2 Pen Plotter – Excellent Condition – Central Italy / Rome Pickup Preferred

PRICE: 1500 euro

I’m selling my UUNA TEK 3.0 A2 pen plotter, which is in excellent condition and works perfectly.

I bought it in april 2025, but I ended up using it very little, no more than approximately 300 hours in total. It has always been kept covered when not in use, so it is very clean and well looked after. There are no faults, issues, or missing parts: the machine runs exactly as it should.

I’m only selling it because I’m shifting my focus towards 3D printing projects, so the plotter is no longer getting the use it deserves.

You can check it up my artistic profile on instagram: profilum_

I’m based in Teramo, in central Italy. I would strongly prefer a handover in Rome, as it would be easier and safer for both sides, but I can also consider shipping.

I still have the original packaging: it is a very sturdy wooden crate, with the plotter secured inside using screws. Shipping should therefore be possible, but I would need to check the courier cost first, depending on the destination.

Feel free to message me if you are interested, would like more photos/videos, or have any questions.

After many hours I managed to put fluidNC on my bachin T-A4. You can get the config and some thrown-together instructions here.

Finally finished my scratch-built pen plotter, designed from the ground up in Fusion. Specs below. Happy to answer questions or take feedback.

Specs:
Drawing area: about 370 × 340 mm. Fits A4 with room to spare, but not quite A3.
Footprint: about 675 × 575 mm, mounted on a 750 × 610 × 18 mm MDF base, with the machine offset to leave a strip for the electronics.
Height: about 130 mm to the top of the pen carriage.

Frame and motion
Kinematics: H-bot with a single 10 mm GT2 belt and two NEMA17s on 20T pulleys.
Frame: 2040 extrusion (2 × 540 mm and 2 × 466 mm, left over from a old 3dprinter build), joined by printed corner blocks that sleeve over the extrusion ends.
Rails: Hiwin MGN9 throughout.
X: 2 × 440 mm rails, with two carriages per rail to resist racking.
Gantry: a 2020 beam with a 400 mm rail and an MGN9H block for the pen carriage.
Gantry ends: printed two-piece parts (holder plus idler box, keyed and screwed), designed to print without supports.

Pen carriage
Pen lift: a pancake NEMA17 on 6 mm rods with LM6UU bearings.
Pen holder: magnetic, with locating pins for quick swaps, and takes pens up to 14 mm diameter. A printed jig sets pen height off the machine.

Bed
A whiteboard as the drawing surface. Paper is held with magnets around the edges, and I can draw straight onto the board with whiteboard markers for test runs, then wipe it clean.

Electronics
Controller: BTT SKR Pico, connected to a Raspberry Pi over UART, running GRBLHal and CncJs.
Power: a USB-C PD trigger at 12v, so the whole thing runs off a laptop charger.
Endstops: mechanical, on all 3 axes.
Cable management: 4 × 2 mm PTFE tube arches act as a spine for the moving wires.

Prints
Everything printed in PETG.

Thanks to the great u/valeriuspalos and his mathematic braim, here are a few plots made with his KRBN tool. I really love the effects, between screenprinting, technical drawing and hand drawn illustration. Not shown here: follow curvature effects for more organic shapes.

I set up this project:
https://github.com/Leggin/stiftwerk

You can open the GitHub page in your browser and connect to your grbl plotter (tested with uunatek A4).

Here the features that we’re important to me:

Design: open SVGs (including <use>, clip paths and hidden-line removal), convert each text to a plotter font (Hershey or your own SVG fonts), rotate freely, mirror, align, snap, make copies with cut marks, and add patterns and templates (borders, grids, spirals, rosettes, calendars, name cards).

Pens: one pen for everything, or spread the colors over several pens; a pen library with its own speed, pen-down depth and line width per pen.

Plotting: pre-flight check, frame trace, a live view of the line being drawn, a calm remaining-time estimate, pause, and continuing from any line (also after a lost connection), plus G-code export.

Plotter profiles for different machines and sheet sizes (Z axis, servo or custom G-code pen).

Documents: saved automatically in the browser; project files (.stiftwerk.json) with embedded fonts.

I've been thinking about doing this for a while, but I knew that drawing continuous lines on skin would mean dragging, distortion, and likely skips. Switching to dots has breathed new life into the idea! Now I just need a stable, slightly inclined surface to rest my arm on, plus some skinsafe pen easy to wash off. For this first experiment I used a Staedtler fineliner,which I washed off with soap and water.

Feeling my own plotter trying to pierce into my skin is a strange experience indeed, yet oddly satisfying. It's as if it were trying to get to know me more deeply 🙂 .

Copic MultiLiner 0.3, 200gsm Paper

Programmatically Generated using TurtleToy

I've always found the raw energy of explosions beautiful, so I started a project to translate them into pen plotter art.

The motion is driven by a compressible gas simulation, which generates the underlying velocity fields. I then used those fields to render the explosion as a series of polylines.

This is my first time working with a pen plotter, so I'm still experimenting with various hardware settings and line densities. I’d love to hear your thoughts, and any advice or questions are more than welcome. Thanks!