FluidCAD: Parametric CAD tool controlled with JavaScript code

What it does

FluidCAD is a parametric CAD tool that combines graphical modeling with JavaScript code control. Users can sketch and shape parts using traditional CAD workflows, then edit and fine-tune designs by writing code. Every CAD feature—sketches, extrusions, cuts, fillets—becomes editable JavaScript that can be version-controlled and reused.

Who it is for

The tool targets mechanical designers and engineers who want parametric control over their models. It appeals to those comfortable with both CAD interfaces and code, particularly users building designs they plan to modify, replicate, or version-control. The focus on assembly features and motion constraints suggests usefulness for mechanical assemblies and kinematic design.

Pricing

The site does not show prices. The desktop application and editor extensions are distributed as free and open source under the MIT license.

How it stands out

FluidCAD bridges CAD and code explicitly. Rather than exporting to code or generating code from graphics, every design action becomes readable, editable JavaScript in real time. The interface includes live rendering as users type, visual guidance, and the ability to reference existing geometry by selecting it directly rather than calculating coordinates manually. The approach treats the code file as the source of truth, with the GUI as an editing tool.

Assembly features appear sophisticated: the tool supports revolute joints, slider constraints, tangent mates, and motion limits. The solver maintains connections between inserted parts as they move.

What a founder should check

First, identify whether potential users actually want to edit CAD in code or if they prefer traditional GUI-first workflows. Incumbents like Fusion 360, SolidWorks, and OpenSCAD already serve the parametric design space; verify whether FluidCAD's code-first hybrid approach genuinely reduces friction versus these alternatives or simply adds complexity for users content with existing tools.

Second, assess switching costs. Professional CAD users have years of muscle memory and libraries of designs in proprietary formats. Check whether the open-source, free positioning attracts hobbyists and startups, or whether it can capture experienced professionals with existing tool investments.

Third, examine the moat. Open source under MIT license means forks and derivatives are trivial. Evaluate whether community, documentation, or specialized features could sustain differentiation, or whether the codebase becomes commoditized quickly.

Thinking of building something like this?

Every launch here is a competitor to somebody's idea. If yours is close, check it against the market before you build: the Full Check names the rivals, the prices and the gaps.