Quote - Open Vue with the default atmosphere. Edit the sun and verify that shadow map is not on. Ok, dont change anything, just close that dialog box. Now, with the sun selected, make the sun volumetric in the object properties panel. Now, edit the sun again and check the shadows tab. In my case, the shadows automatically turn into shadow map.

This only works with the Volumetric atmosphere. The default Spectral atmosphere does not change the shadow type.