Computer-aided design has a reputation problem. For most people, a CAD design means multi-gigabyte installers, clunky license managers, and subscriptions that sometimes cost more than the hardware your PC has. Now there are a lot of design tools that don’t require a subscription, but one of them is quite a solution when it comes to CAD.
That is, until you discover SolveSpace. It’s a lightweight, open-source, fully parametric 3D CAD tool that not only runs natively on your desktop, but also in your browser. No dongles, no cloud lock-in, and no need to worry about hardware specs. Just open a tab and start designing.
I found an open-source alternative to every Adobe app
Turns out, Adobe’s creative suite isn’t your only option.
What SolveSpace is—and why it feels surprisingly capable
So, apart from being lightweight enough to run in a browser and free to use, SolveSpace is also constraint-based, meaning you tell the software the relationships between elements, such as whether a line is horizontal, a circle is tangent to that arc, two distances are equal, and so on, and the solver figures out the geometry from there.
This is a completely different approach compared to the usual method of dragging shapes around a canvas. For anyone doing mechanical or precision work, it’s a lot more reliable. And then there’s the browser angle.
SolveSpace’s codebase is compact enough that the developers were able to compile it for the browser using Emscripten, a toolchain that converts C and C++ code into WebAssembly. SolveSpace is developed primarily as a normal desktop program, and the web version is still experimental. However, it’s still pretty usable, especially with smaller models. The web version also has no dependencies once it’s loaded, meaning you can technically run it offline once the tab is done loading.
- OS
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Windows, Linux, macOS, web Browser
- Developer
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Jonathan Westhues
- Price model
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Free, Open-source
A lightweight, open-source parametric CAD tool for 2D/3D modeling that focuses on constraints, precision, and simplicity without the overhead of traditional CAD suites.
It does more than you’d expect
Sketching, constraints, and real 3D modeling for free
When you first open SolveSpace, you’ll find the interface a bit minimalistic. But don’t let that fool you, the tool covers a surprising range of use cases in both 2D and 3D design.
On the 2D side of the fence, you can sketch with lines, circles, arcs, cubic Bezier curves, and C2 interpolating splines with the option of applying constraints and dimensions as you design. For 3D, you’ve got your standard extrude and resolve options, apart from Boolean operations like union, difference, and intersection to build solid parts. SolveSpace works directly with NURBS surfaces, which means it’s doing exact geometry rather than approximating your curves with polygons.
The program also handles assemblies, letting you link parts together, constrain them relative to each other, and have changes in individual parts propagate automatically through the assembly. There’s also a built-in mechanism simulator that lets you model planar or spatial linkages with pin, ball, or slide joints, animate them, and export the motion data as a CSV file. If you’re working with a custom bracket, enclosure, or mechanical linkage, this feature alone is a lifesaver.
Last but not least, you’ve also got some fairly good export options. You can export to STL for 3D printing, STEP for interoperability with other CAD tools, DXF for laser cutters and waterjet machines, SVG and PDF for technical drawings, and even Three.js-compatible HTML files for in-browser viewing or sharing.
Lightweight, but seriously fast and capable
Apart from being able to run in a single browser tab, the overall footprint of the desktop app is rather small, too. On Windows, you don’t even need to install it as it’s distributed as a standalone EXE file that boots within seconds. Compared to a heavier program like Fusion 360, that’s saving you gigabytes of storage space and memory resources. Not to mention the need for an internet connection to verify the license.
SolveSpace’s lightweight nature is intentional, as the entire program was built around a sophisticated constraint solver, and everything else is kept lean to fulfill that purpose. This also means you can run SolveSpace on just about any computer and don’t require the mammoth hardware specifications that most big-name 3D design or CAD programs require. As long as you’ve got a computer and the EXE file (or a loaded browser tab), you’re good to go.
It’s not perfect—and that’s okay
Where it falls short compared to heavyweight CAD tools
SolveSpace isn’t trying to replace SolidWorks or Fusion 360 for a professional team of mechanical or aerospace engineers, and the program is very transparent about that. Better developed and paid for designing programs still come with better features that make designing and working on engineering problems easy. The moment your design starts getting a bit too complex, SolveSpace will start to show cracks. Regardless, it’s one of those open-source programs I’d happily buy.
It’s meant for the vast majority of hobbyists, makers, electronics enclosure or small-batch part designers, and students learning parametric CAD for the first time. SolveSpace makes CAD designing accessible to anyone, whether or not they have the money or hardware. And the fact that it fits in your browser tab while running a full local solver is something programs a lot more expensive can’t claim to do.
