For a limited time, you can get the unparalleled precision of Catchbook Drawing at a discount! It will be free on iOS and Windows devices and just 99 cents on Android. The one-time purchase and download is good forever, so once you have it, it's yours.
Catchbook Drawing converts your freehand sketches into mathematical curves you can push, pull, and “snap” to other geometry. Accurate dimensions are automatically generated when you draw with Dimensions on, and these can be placed or edited in a few taps of your stylus or finger.
Note: You will have to go through a purchase sequence in the store for both iOS and Windows, however, you will not be charged. See below for an example of what that looks like.