From what I heard, I think that the Lego Movie made their lego models in LDD, and than exporting the models to Maya, and using maya to make subsurf models. I think that they found a way to make their subsurf models automatically be placed in the correct place using data from LDD? Does anyone know how to do this? (I realize it's a hefty topic)
According to the Lego Digitial Designer manual it allows to export LXF, LXFML and LDraw files.
Export. Export lets you create LXF, LXFML and LDraw files that can be opened in other applications
There are community developed Blender add-ons such as ImportLDraw by Toby Nelson that allow to import these models.