Block CAD 1.0

You can save your models, or save pictures of them (.bmp, .jpg), even reuse a complete model as a part in another model. Everything can be controlled with the mouse, but it's also possible to use the keyboard for most of the commands, making 'routine building' more effective, and there is a minimum of text involved, to make it easier for kids. BlockCAD is not a full CAD program, the pieces can only be placed 'studs up', and rotated in steps of 90 degrees. It is impossible to draw pieces that are partly inside other parts, which excludes almost all of the Lego Technic line, but there's still a lot of fun to be had with it.