Invert SVG graphics b/w

Take some drawing

Duplicate the drawing

CTRL + D

Leave the items selected!

Break apart the selection

CTRL + K

Leave the items selected!

Union the selection

Doing this we will get the complete outline of the objects.

Leave the items selected!

Run exclusion

Select the original object and the new outline merge object from previous step, then run Exclusion on both. The z ordner does not matter.