I'm a little late to this post but take a look at SolveSpace, they have a native Linux client and it's free (GPLv3). The downside is you'll have to build it yourself. - Source: Reddit / 29 days ago
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LibreCAD - An open source 2D CAD application for Windows, Apple and Linux.
Planner 5D - Home Design Software & Interior Design Tool ONLINE for home & floor plans in 2D & 3D. Read more about Planner 5D.
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SolidWorks - Dassault Systèmes SolidWorks Corp. develops and markets 3D CAD design software, analysis software, and product data management software. SolidWorks is the leading supplier of 3D CAD product design engineering software.