JustCAD is described as 'JustCad is designed, to make cad drawing as simple as possible'. There are more than 10 alternatives to JustCAD for a variety of platforms, including Windows, Mac, Linux, Online / Web-based and BSD. The best alternative is LibreCAD, which is both free and Open Source. Other great apps like JustCAD are DraftSight (Paid), QCAD (Free Personal), progeCAD Smart (Free Personal) and Draft it (Freemium).
NttCAD: free, simple 2D/3D CAD software, multi-platform (works on Windows, Mac, linux...). Programmable in Java language. Small program size and fast download. Saves in autocad dxf, svg and NttCAD formats.
Ideal for garden design, mechanical engineering drawings, electrical / electronic, building and room plans, and general diagramming. Output in PDF format for the web. Copy and paste graphics. Create standard symbols to re-use. Scale, mirror and rotate.
TrueCAD is an economical 2D Drafting and 3D Wireframe Modeling CAD software meant for Engineers, Architects and other technical consultants. TrueCAD works in native DWG & DXF CAD software to create and edit drawings.