DoodleCAD

DoodleCAD is a vector-based illustration and CAD tool that gives Mac OS X users the tools they need to do illustrations, diagrams, and mechanical drawings like a pro - at a very affordable price.
With DoodleCAD, designed to be both powerful and intuitive, you can create art for art's sake or a scale drawing of your house remodeling plans.

Draw a duck or a full set of scaled and dimensioned views of that clever invention you've been meaning to build some day. DoodleCAD has a full set of standard tools for making simple shapes as well as complex curved and straight paths and text. Path and shape editing in DoodleCAD is simple and intuitive; just a click and drag. Show the exact size of individual parts or segments with just a few mouse clicks. When you're done you can export to standard image formats including TIFF, JPEG and PDF or copy just part of the drawing and paste it into iWork Pages or Photoshop.
Note: This application contains in-app and/or external module purchases.