Here’s an interesting app that has been open sourced by Bartosz called Revolved. Revolved is a 3D modeling app that has a unique interface in which the user draws the 3d models by drawing curves and has the ability to export the models for use in other modeling programs.

Here’s a screenshot from the App Store showing off some models drawn in Revolved:

You can find the Revolved app source code on Github here.

You can download revolved in the App Store here.

You can also read more about techniques used in drawing bezier curves on Bartosz’s blog.