Here is what happens the moment you install one:
: A centralized panel that provides quick access to all scales, layers, and tool groups. adobe illustrator cad tools plugin
If you aren't ready for a full plugin, you can achieve basic CAD-like results using native Illustrator tools: What is a CAD Tools Plugin for Illustrator
Access specialized tools for filleting, chamfering, and creating arcs by radius that native Illustrator tools don't offer. Leading CAD Plugins for Adobe Illustrator 1. Hot Door CADtools adobe illustrator cad tools plugin