BRL-CAD is a constructive solid geometry (CSG) solid modeling computer-aided design (CAD) system. It includes an interactive geometry editor, ray tracing support for graphics rendering and geometric analysis, computer network distributed framebuffer support, scripting, image-processing and signal-processing tools. Developed by U.S. Army Research Laboratory
License: Open Source
BRL-CAD is a robust tool focused on high-fidelity modeling and simulation, making it suitable for engineering applications. In contrast, SolveSpace excels in parametric and assembly modeling, catering more to mechanical design needs, with a user-friendly interface.