Start3d();
Putaxes3d(4);
Xyzax3data("","x=[-5,5]","y=[-5,5]","z=[-5,5]");

fd1=[
 "z=4-(x^2+y^2)",
 "x=R*cos(T)","y=R*sin(T)",
 "R=[0,2]","T=[0,2*pi]","e"
];

if(Isangle(),
 Sf3data("1",fd1);
,
 Startsurf();
 Sfbdparadata("1",fd1);
 Crvsfparadata("1","ax3d","sfbd3d1",fd1);
 Paramplot("1","[1,t]","t=[0,2*pi]",["Num=50","nodisp"]);
 Crv2onsfparadata("1","gp1","sfbd3d1",fd1,["Color=red"]);
 if(Gccexists(),
   ExeccmdC("1",[""]);
 );
);
Windispg();