LeoCAD

LeoCAD is a free and open-source 3D CAD program for creating virtual Lego models by using parts from LDraw library.^[5][6][7] It was developed by Leonardo Zide in 1997.^[8]

LeoCAD

Screenshot Screenshot of Flyer build from LEGO Masters Denmark rebuilt in LeoCAD
Original author(s)	Leonardo Zide
Initial release	1997; 28 years ago (1997)[1]
Stable release	23.03[2] / March 19, 2023; 22 months ago (2023-03-19)[2]
Repository	github.com/leozide/leocad
Written in	C++[3]
Operating system	Windows MacOS Linux[4]
Size	27,5 MB
Available in	English
Type	Computer-aided design
License	Gplv2
Website	www.leocad.org

History

LeoCAD is developed and released by Leonardo Zide around 1997 under GPL v2 free and open source software license.^[9] Its written in C++ and uses Qt as GUI.^[10] At first it was a standalone CAD software with its own brick library, but soon it was updated to adopt the LDraw library and file format, an unofficial Lego parts collection that was very popular at the time.^[11] As of 2024, LDraw contains over 10.000 pieces and still gets updated with new bricks.^[12][13]

In 2021, Leonardo received James Jessiman Memorial Award from LDraw community for his creation of LeoCAD and contributions to the parts library.^[14]

Features

Measuring LDraw parts size in LeoCAD with custom "ruler" part (ruler tick: 1 mm)

LeoCAD allows users to build Lego models in a CAD environment with LDraw bricks library which is installed by default to make it easier for users to start building. Apart from LDraw, it is possible to import other custom brick libraries.^[15][16] LeoCAD also enables users to track each part which can be used to generate step-by-step instruction just like in official Lego sets.^[17]

Parts can be selected from the part selector and directly dragged into the building area where they can be moved or rotated via arrows with customizable precision. Building area provides 6 virtual cameras built-in which can be used to focus on different parts of the build.^[18] Other tools include additional cameras for alternative view angles, omni lights and spotlight.

POV-Ray rendering of the flyer model generated inside LeoCAD

By default, LeoCAD saves builds as LDraw-compatible LDR and MPD (Multi-Part Document) file format. It supports exporting builds as Wavefront OBJ, COLLADA DAE and Autodesk 3DS models and curating brick lists in CSV, HTML and BrickLink-compatible XML. It also has a built-in POV-Ray render option.^[19][20]

Usage

LeoCAD and LDraw parts are mentioned in academic research and used in projects. In 2008, a group of academics from Technical University of Lisbon wrote a paper that reviews available LEGO CAD tools of the time including LeoCAD and made suggestions on how to improve virtual brick building experience. They created their own software with gravity and collisions, and compared it with LeoCAD in terms of efficiency.^[21] In 2019, LeoCAD was used for designing virtual 3d model of a Lego Mindstorms based robot for autonomous vehicle simulation research which got revealed in an IEEE conference of that year.^[22]

See also

• Bricklink Studio
• Lego Digital Designer

References

1. "LeoCAD". Chip.
2. "Version History | LeoCAD". www.leocad.org. Retrieved 2024-11-12.
3. "Search · · leozide/Leocad". GitHub.
4. "LeoCAD Downloads".
5. Woo, Michelle (July 16, 2018). "Here's How Your Kids Can Build Lego Models Digitally and Then Buy Their Own Creations". Lifehacker. Retrieved December 20, 2021.
6. Kenlon, Seth. "Play with virtual LEGOs using open source tools | Opensource.com". opensource.com. Retrieved 2024-11-20.
7. Rollins, Mark (20 December 2012). Practical LEGO Technics (1st ed.). Apress. pp. 16–19. ISBN 9781430246121.
8. "LEGO raytracing".
9. P, Madeleine (2024-07-16). "LeoCAD: The Free 3D Modeling Software Inspired by LEGO". 3Dnatives. Retrieved 2024-11-12.
10. Emms, Steve (2023-10-17). "LeoCAD - design virtual models you can build with LEGO bricks". LinuxLinks. Retrieved 2024-11-21.
11. "James Jessiman Memorial Award for 2021 awarded to Leonardo Zide". forums.ldraw.org. Retrieved 2024-11-12.
12. "LDraw.org Library Updates". library.ldraw.org. Retrieved 2024-11-12.
13. Trisha (2017-08-06). "LeoCAD is a Virtual LEGO Software for Windows, Mac and Linux". Retrieved 2024-11-21.
14. "James Jessiman Memorial Award for 2021 awarded to Leonardo Zide". forums.ldraw.org. Retrieved 2024-11-12.
15. "Parts Library | LeoCAD". www.leocad.org. Retrieved 2024-11-20.
16. Santos, Tiago; Ferreira, Alfredo; Dias, Filipe; Fonseca, Manuel J. (2008). "Using Sketches and Retrieval to Create LEGO Models". Technical University of Lisbon – via Eurographics Digital Library.
17. Bedford, Allan (2005). The Unofficial LEGO Builder's Guide (1st ed.). No Starch Press. pp. 187–201. ISBN 9781593270544.
18. Rollins, Mark (20 December 2012). Practical LEGO Technics (1st ed.). Apress. pp. 18–19. ISBN 9781430246121.
19. Emms, Steve (2023-10-17). "LeoCAD - design virtual models you can build with LEGO bricks". LinuxLinks. Retrieved 2024-11-21.
20. Trisha (2017-08-06). "LeoCAD is a Virtual LEGO Software for Windows, Mac and Linux". Retrieved 2024-11-21.
21. Santos, Tiago; Ferreira, Alfredo; Dias, Filipe; Fonseca, Manuel J. (2008). "Using Sketches and Retrieval to Create LEGO Models". Technical University of Lisbon – via Eurographics Digital Library.
22. Clark, G. W.; Andel, T. R.; Doran, M. V. (2019). Simulation-Based Reduction of Operational and Cybersecurity Risks in Autonomous Vehicles. 2019 IEEE Conference on Cognitive and Computational Aspects of Situation Management (CogSIMA). Las Vegas, NV, USA. pp. 140–146. doi:10.1109/COGSIMA.2019.8724160.

Bibliography

• T. Santos, A. Ferreira, F. Dias & M. J. Fonseca. Using Sketches and Retrieval to Create LEGO Models. Eurographics Workshop on Sketch-Based Interfaces and Modeling, 2008.
• Daniel Mendes, Alfredo Ferreira. Virtual LEGO Modelling on Multi-Touch Surfaces. WSCG'2011 Full Papers Proceedings, 2011. ISBN 978-80-86943-83-1
• Van Thanh Tran, Dongho Kim. An Application of Virtual Reality in E-learning based LEGO-Like Brick Assembling. School of Global Media, Soongsil University, Seoul, Korea, 2016.

External links

• Official website
• "About LeoCAD". GitHub. 9 December 2021.
• BrickHub build library, LDraw builds designed mostly using LeoCAD