Lin Xin-Liang (林信良), also known online as **caterpillar** and **JustinSDK**, was a Taiwanese software engineer, technical writer, translator, and educator. For people working with OpenSCAD, his most enduring contribution is dotSCAD: a library built around reusable, composable tools for procedural geometry.

## A programmer who taught in public

Lin maintained openhome.cc—also known as 良葛格學習筆記—where he published programming tutorials and educational material. He worked in technical training, served as a consultant at a Sun Microsystems training center, and was an authorized Oracle instructor.[1][2]

Beginning in April 2012, Lin wrote the 程式人 column for iThome. The publication's memorial collection credits him with 459 articles produced across a decade, covering languages including C, C++, Java, Ruby, Python, JavaScript, and Haskell.[1][2]

That breadth matters to his CAD work. dotSCAD does not treat modeling as a set of isolated shapes. It approaches geometry as a programming vocabulary: functions and modules that can be combined, transformed, and reused.

## dotSCAD and code-driven CAD

Published under the JustinSDK name, dotSCAD provides OpenSCAD utilities for curves, surfaces, transformations, path operations, and algorithmic construction.[3] Its organization encourages designs to be assembled from smaller operations instead of copied as one-off scripts.

Lin also published generative designs on Thingiverse.[4] These objects provide a practical view of the same idea: a model can be the visible result of an algorithm, while the reusable technique remains available for the next design.

This is why his work is relevant to Varcad. A browser-based parametric workspace depends on the same underlying belief—that source code, reusable libraries, rendered geometry, and project history belong close together.

## Continuing influence

Lin died in 2022 at the age of 48. Independent reporting from TVBS described the response from programmers who had learned from his articles, while iThome assembled a memorial collection of his work.[1][7]

The OpenSCAD community also remembered him through its 2022 Advent Calendar, which included work connected to his caterpillar designs.[5][6] dotSCAD remains available as both a working library and a record of an approach to teaching: make the technique concrete, publish it, and leave enough structure for somebody else to build on it.

## References

1. [林信良紀念專輯](https://www.ithome.com.tw/caterpillar), iThome, accessed March 20, 2026.
2. [林信良](https://www.ithome.com.tw/users/%E6%9E%97%E4%BF%A1%E8%89%AF?page=1), iThome author profile, accessed March 20, 2026.
3. [dotSCAD](https://github.com/JustinSDK/dotSCAD), GitHub, accessed March 20, 2026.
4. [Designs by JustinSDK](https://www.thingiverse.com/justinsdk/designs), Thingiverse, accessed March 20, 2026.
5. [OpenSCAD Advent Calendar 2022](https://github.com/openscad/openscad-advent-calendar-2022), GitHub, accessed March 20, 2026.
6. [Advent Calendar 2022](https://openscad.org/advent-calendar-2022/), OpenSCAD, accessed March 20, 2026.
7. [程式達人「良葛格」驚傳離世！全網悼：看他文章受益良多](https://news.tvbs.com.tw/life/1964441), TVBS News, November 16, 2022.

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*This article was adapted from Wikipedia's [“Draft:Lin Xin-Liang,” revision 1344418000](https://en.wikipedia.org/w/index.php?title=Draft:Lin_Xin-Liang&oldid=1344418000), available under the [Creative Commons Attribution-ShareAlike 4.0 License](https://creativecommons.org/licenses/by-sa/4.0/). The source draft was declined through Wikipedia's Articles for Creation process on March 20, 2026. This Varcad edition has been edited and reorganized for an audience interested in OpenSCAD and code-driven CAD.*

Ideas built in code and geometry.

Lin Xin-Liang, dotSCAD, and the Craft of Code-Driven CAD