//--- macro tools




//--- add to difference
#declare paper_Cut_Z =
union{ 
    plane{ <1,0,0> 0 }                        //--cut at center X
    plane{ <0,0,-1> 0 translate <0,0,.002>}   //--pos Z end
    plane{ <0,0,1> 0 translate <0,0,-.002>}   //--pos Z start     
    } 
       

//--- add to difference      
#declare paper_Cut_Z_Curved =
union{ 
    plane{ <1,0,0> 0 }                                      //--cut at center X
    sphere{ <0,0,0> 50    translate <0,0,50> }             //--pos Z end
    sphere{ <0,0,0> 50.01 translate <0,0,50> inverse}      //--pos Z start     
    } 
    


