Free CAD application for creating LEGO models. Fully compatible with the LDraw Standard and related tools. It reads and writes LDR and MPD files so you can share and download models from the internet. LeoCAD is optimized for large models over 4,000 pieces. Tons of models inside. Has an intuitive interface, designed to allow new users to start creating new models without having to spend too much time learning the application. At the same time it has a rich feature set, enabling experienced users to build models using more advanced techniques.