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Posted on Nov 28 • Originally published at terabyte.systems on Nov 24

µcad: Declarative Code-Driven CAD with Rust

#rust #programming

The world of computer-aided design (CAD) has long been dominated by graphical user interfaces (GUIs), offering intuitive drag-and-drop experiences for creating intricate 2D sketches and 3D models. However, a growing segment of engineers, designers, and programmers are turning to a more programmatic approach: code-driven design. This method, which treats design as code, offers unparalleled benefits in terms of precision, automation, and version control. Into this evolving landscape steps µcad (pronounced “micro-cad”), a new open-source programming language built with Rust, poised to redefine how we approach parametric design.

The Paradigm Shift to Code-Driven Design

Traditional CAD software, while powerful, often presents challenges in managing complex parametric designs, automating repetitive tasks, and collaborating effectively through version control. Imagine tweaking a single dimension across hundreds of parts, or trying to merge design changes from multiple collaborators without overwriting work. These scenarios highlight the limitations of purely visual workflows.

Code-driven design, on the other hand, leverages the strengths of programming languages to define geometric models. This approach empowers designers with:

Parametric Control: Easily modify design parameters through variables and functions, allowing for rapid iteration and customization.
Version Control: Integrate with Git and other version control systems, enabling robust change tracking, branching, and merging of design files—a workflow familiar to software developers.
Automation: Script complex operations, generate variations, and automate manufacturing preparation tasks, reducing manual effort and potential errors.
Reproducibility: Designs are defined by code, ensuring exact reproducibility of models across different environments and over time.

OpenSCAD has been a pioneer in this space, offering a functional, text-based approach to solid modeling. However, as the demand for more sophisticated and robust code-driven tools grows, new languages like µcad are emerging to address its limitations and introduce advanced features.

Photo by Shubham Dhage on Unsplash

µcad’s Core Philosophy and Features

µcad is presented as a novel open-source programming language specifically designed for generating 2D sketches and 3D objects. It shares the fundamental ethos of OpenSCAD—being fully programmable, open source, and text-based—but distinguishes itself with a more declarative design approach. This means designers focus on what the design should be, rather than how to construct each geometric primitive step-by-step.

Built on the Rust programming language, µcad inherently benefits from Rust’s focus on performance, memory safety, and concurrency. This foundation promises a robust and efficient environment for complex geometric computations.

Key features that set µcad apart include:

Strong Type System with Units: Unlike many scripting languages, µcad incorporates a strong type system that can handle units (e.g., millimeters, inches). This is a game-changer for engineering applications, preventing common errors related to unit mismatches and ensuring dimensional accuracy.
Module System and Standard Library: µcad provides a comprehensive module system, allowing designers to organize their code logically and reuse components effectively. It includes a standard library with common geometric primitives and operations, accelerating development.
Binary Operators and Assignments: The language supports intuitive binary operators and variable assignments, making expressions for transformations and manipulations more natural and readable.
Attributes for Metadata: Users can attach metadata to geometries. This feature is invaluable for downstream processes, allowing for the inclusion of material properties, manufacturing tolerances, or assembly instructions directly within the design file.
Align and Distribute Operations: Built-in functionalities for aligning and distributing objects simplify the creation of structured layouts and patterns, common in mechanical design and architectural planning.
SVG Export: Beyond 3D models, µcad can generate 2D sketches and offers SVG export, making it suitable for laser cutting, CNC routing, and other 2D fabrication methods.

A significant technical detail is µcad’s reliance on the Manifold geometry kernel. This means µcad operates primarily with mesh-based geometry, a fundamental distinction from CAD systems that use Boundary Representation (BREP). While BREP offers precise, mathematically defined surfaces and edges, mesh-based modeling excels in flexibility, especially for complex or organic shapes, and is often preferred for 3D printing and rendering applications. Understanding this distinction is crucial when considering µcad for specific design tasks.

Advantages for Modern Engineering Workflows

The features of µcad translate into several compelling advantages for professionals in various fields:

Enhanced Precision and Repeatability

With its strong type system and unit handling, µcad minimizes the risk of dimensional inconsistencies. Designs are precisely defined by code, eliminating the ambiguity that can sometimes arise from visual manipulations in GUI-based CAD. This makes it ideal for applications requiring high accuracy, such as aerospace components or intricate mechanical parts.

Streamlined Version Control and Collaboration

By treating designs as code, µcad seamlessly integrates with established software development practices. Teams can leverage Git for version control, allowing for:

Atomic Commits: Track every change to the design.
Branching and Merging: Experiment with design variations in separate branches and merge changes collaboratively, resolving conflicts programmatically.
Design History: Easily revert to previous iterations, providing an invaluable safety net for complex projects.

Automation and Parametric Scalability

µcad’s programmatic nature unlocks vast potential for automation. Designers can write scripts to:

Generate families of parts based on varying parameters.
Create complex patterns or textures algorithmically.
Automate the creation of assembly instructions or bill of materials (BOM) based on embedded metadata.

This capability is particularly beneficial for designs that require many similar but slightly different components, or for exploring a wide design space efficiently.

Photo by Locanam 3D Printing on Unsplash

µcad in the Open-Source CAD Ecosystem

µcad enters a vibrant open-source CAD ecosystem, joining tools like OpenSCAD, FreeCAD, and CadQuery. Its position is unique, building upon the “code-first” philosophy while introducing modern language features and a declarative paradigm.

Compared to OpenSCAD , µcad offers significant advancements such as a module system, a strong type system with units, and more expressive syntax for defining geometry. These improvements aim to address some of the “clunky” aspects users have experienced with older code-driven tools.

While FreeCAD offers a comprehensive GUI-based parametric modeling experience with Python scripting capabilities, µcad provides a purely code-centric environment, appealing to users who prefer a text-editor-driven workflow for greater control and automation. Similarly, CadQuery offers a Pythonic way to build parametric models, but µcad introduces its own purpose-built language and a declarative syntax that might resonate more with certain design philosophies.

The choice of the Manifold geometry kernel is a defining characteristic, differentiating it from BREP-based solutions like FreeCAD (which uses OpenCASCADE Technology). This makes µcad particularly strong for applications where mesh integrity and direct mesh manipulation are crucial, such as preparing models for 3D printing or creating sculptural forms.

Photo by GLOBALDSIO IT SOLUTION on Unsplash

Getting Started with µcad

As an open-source project, µcad’s development is community-driven. The project is still in its early stages but is “increasingly stable,” with active development and new features being added regularly. The official project repository has moved to Codeberg.org, reflecting its commitment to open-source principles.

For those interested in exploring µcad, the project’s website (microcad.xyz) serves as the primary resource. It provides updates, examples, and mentions a forthcoming “µcad book” which will detail the language’s features and usage. While a direct “live coding” workflow similar to OpenSCAD’s immediate visual feedback is a common desire among users of code-driven CAD, the µcad website does showcase “live coding video” examples, indicating a focus on an interactive development experience.

To begin, users would typically clone the repository, build the tool (given its Rust foundation), and start writing µcad code in their preferred text editor. The open-source nature means that contributing to the project, reporting issues, or suggesting new features is encouraged.

Conclusion

µcad represents an exciting evolution in the field of code-driven design. By combining a declarative approach with the performance and safety of Rust, and integrating modern features like a strong type system with units, it offers a powerful new tool for engineers and designers. Its focus on programmatic control, automation, and seamless integration with software development workflows positions it as a strong contender for complex parametric modeling and collaborative design. As the project continues to mature, µcad has the potential to become a cornerstone for a new generation of open-source, code-first mechanical and architectural design.

References

Reddit (2025). µcad, a new language for CAD written in Rust : r/openscad.
Hacker News (2025). µcad: New open source programming language that can generate 2D sketches and 3D.
microcad.xyz (2025). µcad programming language.
Sculpteo (2025). Top 18 of the best open-source CAD software in 2025.

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