Tutorial: How to make Dodechahedron
Here is another way to make a same thing but with help of sheetmetal features of SW. It used base flange, cut holes and sketched bend features.
First make sketch as you see on pic with 5 side polygon diameter 250mm and with base flange make a sheetmetal plate 1mm thick
Now cut a holes -dia 2 mm on problematic corners - think where is!
Now use sketched bend at angle 63.43 degrees with radii 0.01mm
Next bending with same parameters
Final bending with same parameters.
Here is flat pattern from sheetmetal
And colored part