It,s not the first time it happens to me. Extrusion produces fully sliced up body (each line is like a cut of a knife). Previous times it had happened, I had to “clean up” completely the drawing to be extruded, leaving only the perimeter lines, which worked out.
Today, I’m not even able to solve the extrusion that way, as the extrusion of a single body is also not working “extrusion failed”. Any ideas as to how to circumvent whatever I am doing wrong?! Thank you very much!