S-TIER repo
ln + vpype — 3D scenes to hidden-line vector art for pen plotters
100k ft — What is this?
ln + vpype — 3D scenes to hidden-line vector art for pen plotters
50k ft — Why care?
Michael Fogleman's ln (Go) renders 3D scenes as 2D vector paths by ray-testing each path segment for visibility, supporting CSG, math surfaces and procedural cities. vpype then merges and sorts paths for plotting, cutting pen-up travel 86% in this example. Both MIT licensed, output straight to SVG.
10k ft — Key takeaways
• Animate a moving camera for line-art animation
• Texture is defined by which paths you put on a surface
• link: https://github.com/abey79/vpype/tree/e593ff05c2b13e48be2b3aa10e1c8d71c1b21dc0
• link: https://github.com/fogleman/ln/tree/12e6c6e7445909f817f1b8d5581be4255ffa1437
• ln outputs vector paths, not pixels, so 3D scenes plot in real ink
5k ft — Tools & techniques
ln, vpype
CSG, hidden-line removal, path optimization, ray casting
1k ft — Deep-dive / try it
ln + vpype — turning 3D scenes into lines for drawing.
① Build a 3D scene → ② remove hidden lines → ③ export vector paths → ④ arrange the drawing order.
ln removes lines hidden by the geometry. vpype joins and reorders the paths for pen plotting.
These scenes use ln's original examples with added camera motion. In this example, vpype linemerge + linesort reduced pen-up travel by 86% (105,271 → 14,926 px). This measures distance, not the time of a real pen plotter.
Which scene would you turn into a print, an animation, or a pen plot?
The cover is an AI-generated illustration based on the line drawings.
ln + vpype는 3D 장면을 그릴 수 있는 선으로 만들고, 그리는 순서를 정리하는 도구입니다.
① 3D 장면 만들기 → ② 가려진 선 지우기 → ③ 벡터 경로로 내보내기 → ④ 그리는 순서 정리하기.
ln은 다른 형상에 가려진 선을 없애요. vpype는 경로를 연결하고 순서를 바꿔 펜 플로팅을 준비합니다.
ln의 원본 …
Transcript excerpt
Today's open source project is LN, the 3D lineart engine. These scenes are 3D, but the output isn't pixels, it's lines. It's by Michael Fogelman, written in Go. He made it so he could plot 3D drawings with his pen plotter. An OpenGL pipeline gives you a raster image. LN gives you 2D vector paths. Every shape is covered in 3D paths. LN chops them into tiny pieces, and from each point shoots a ray toward the camera. If nothing is hit, the point is visible. If something is in the way, it's hidden and never drawn. So the texture is just the paths you choose. Over-eyed paths and a cube become stripes. It also does solid geometry. A sphere trimmed by a cube and drilled by three cylinders. Math functions become surfaces, random walks become strings of beads, and random boxes become a city. Before plotting, there's V-pipe by Antoine Baylor, a Swiss army knife for plotter graphics. Here, line merge and line sort cut the pen up travel by 86%. For visual work, render a scene straight to SVG. Plot it in real ink, or turn a moving camera into a line animation. Both are MIT licensed. Thank you. Bye.