Lego Digital Designer, or LDD, is a CAD-like software for Mac OS X and Windows. It is distributed by the Lego Group through their website as freeware. The software can be used to design Lego models, which can then be ordered from the Lego Factory website. Estimation of available bricks is above 1,000. Pick-A-Brick has 999 of these elements. Users can also take "screenshots" of their models and save it to their hard disk. As of 2008[update], three versions have been released of Lego Digital Designer. The latest one has more bricks and sections.

1. Lego Digital Designer Antonio Dell’Ava (creativecaos@gmail.com) Università degli Studi di Siena laurea magistrale in DAC (Design di Ambienti per la Comuniczione) corso di Grafica 3D http://ldd.lego.com/ 3d & web2.0