Xu 50; //Length of upstream duct before diffuser section Yu 10; //Half-width of duct before diffuser section Xd 500; //Length of downstream duct after diffuser section Yd 25; //Half-width of downstream duct after diffuser section Ld 100; //Length of diffuser section Zf 5; //Thickness in Z-direction Xo #calc "$Ld + $Xd"; Xup #calc "-$Xu"; Yul #calc "-$Yu"; Ydl #calc "-$Yd"; Zr #calc "-$Zf";