CAD Markup is a powerful tool designed specifically for professionals in fields such as architecture, engineering, and construction, developed by Guthrie CAD/GIS Software from Australia. It allows users to annotate and mark up CAD drawings with ease, enhancing communication and collaboration throughout the design and review process.

AutoCAD is undoubtedly the most popular and powerful CAD modeling software. But as a commercial software, it is really, really expensive. FreeCAD is a free, open-source, cross-platform and general-purpose 3D CAx (CAD, CAM, CAE), PLM modeling tool specially designed for home user/hobbyist, experienced CAD user, programmer or educator.