How to export 3D model from Designspark Mechanical to Designspark PCB

Hi, I'm working on a project that uses arduino. I have successfully modelled the schematics and PCB for arduino in Designspark PCB. But, I need to build the enclosure for my PCB, and that means I have to model a 3D view for arduino. I've found the 3D model of arduino in DesignSpark Mechanical, but don't know how to bring that in the "3D View" tab of DesignSpark PCB as the 3D model for arduino. Any help is greatly appreciated.