DraftSight - Discover Dassault Systèmes®' DRAFTSIGHT™ Professional CAD software that lets you create, edit, view and markup any kind of 2D drawing. Learn more here.
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Blender - Blender is the open source, cross platform suite of tools for 3D creation.
LibreCAD - An open source 2D CAD application for Windows, Apple and Linux.
TurboCAD - TurboCAD is a CAD software suite, with several different feature levels.