CAD Design Electronic enclosure STP file creation

We require a housing design for a LED light up module for a cosplay T-shirt, the piece will contain a simple PCB, LED's in a pattern, batteries and on/off switch. We require a CAD design for the Module housing The housing can be modified from a previous sample that was made some time ago or designed from scratch. the housing will require a battery door and hole for a toggle switch. The module is designed to be placed in a pocket on the underside front chest of a t-shirt and shine through the fabric please see attached for images of the effect required and previous sample made