+ linear_extrude(height=pbase_thick){
+ difference(){
+ hull(){
+ ArchProfile(true);
+ ArchProfile(false);
+ }
+ intersection(){
+ MainCutout();
+ translate([0, -inner_pbase_thick
+ - (inner_pbase_rad - arch_in_rad)])
+ ArchCircle(inner_pbase_rad);
+ }
+ }