#6381
LeoCAD is a 3D CAD program for creating virtual LEGO models by using parts from LDraw library, developed by Leonardo Zide in 1997, using C++. It's free and open-source, and works on Windows, Mac and Linux platforms. It enables users to create their own LEGO models as they wish.

#6357
As one of the most successful and popular toys, LEGO bricks have great appeal to both adults and children. But there are so many kinds of LEGO parts, it is not easy to store and manage so many parts and freely build the creations in mind. So back in 2002, LEGO started developing LEGO Digital Designer, whose original vision was to allow people to build bricks on a computer, have fun and share their creations.