Attached you will find the STL file to 3D print the necessary internals for making a Icosidodecahedron like this. I have also included the generic SVG file. If you want to change the sizing of the shape, just know that the holes are 1/2" from the corners. It’s designed to work with M3 screws, but I’ve also use 6-32 with a bit of extra effort. If you don’t have access to a 3D Printer, you can buy these shapes here.
You need to print 30 of these for a Icosidodecahedron.
Icosidodecahedron-metric.stl (127.1 KB)