This Raspberry Pi case is for the brand new model 4B. This case is low profile and the top is designed for mounting a Noctua 40mm fan, it also features multiple sets of holes on the bottom surface to allow Zip ties to be threaded through for easy mounting (I recommend putting the zip ties in before installing the Pi). Also, this case allows the Pi to be snapped in without the need for additional hardware. The opening for the GPIO pins will also accommodate a standard notched 40-pin ribbon cable connector.
*Note: These parts are interchangeable with my previous Raspberry model 4B case, however the bottom on this design has significantly more ventilation slats.
YOU NEED TO ROTATE THE TOP 180 DEGREES ON THE Y AXIS IN YOUR SLICER
About the design process...
I run Ubuntu Linux on all my home computers. This limits my choices for CAD software so I have taught myself how to use FreeCAD since there is a native Linux version that seems to be getting more stable as time goes by.