A CAD platform that lives in the browser. Models are not saved as local files but kept as a version chain by the service, several designers can work on the same model at once, and drawings stay linked to parts and bills of materials. The free tier targets personal non commercial use, and documents are public by default.

A two dimensional drafting program that has done one job for twenty years: layers, blocks, dimensions and scaled printing, exchange format support, and almost no demand on hardware.

Engineering collaboration runs on drawings, and drawings run on a format. AutoCAD has held its position half on capability and half on ecosystem: its native format is the shared language between design offices, contractors and review bodies, and layer, block and reference management is mature to the point of instinct.

SketchUp first appeared in 2000 and now belongs to Trimble. Its core gesture pushes a face into a solid and pulls a line into a face, which is why architects and stage designers keep using it; the browser version carries a free tier for personal projects.

A two-dimensional drafting program under the GPL: more than forty construction tools, a library of over 4,800 standard parts, command-line converters and a scripting interface, with a free community edition.