import graph3; import contour; currentprojection=orthographic(1,-2,1); currentlight=White; size(12cm,0); real sinc(pair z) { real r=2pi*abs(z); return r != 0 ? sin(r)/r : 1; } render render=render(compression=Low,merge=true); draw(lift(sinc,contour(sinc,(-2,-2),(2,2),new real[] {0})),red); draw(surface(sinc,(-2,-2),(2,2),Spline),lightgray,render); draw(scale3(2*sqrt(2))*unitdisk,paleyellow+opacity(0.25),nolight,render); draw(scale3(2*sqrt(2))*unitcircle3,red,render); xaxis3("$x$",Bounds,InTicks); yaxis3("$y$",Bounds,InTicks(beginlabel=false)); zaxis3("$z$",Bounds,InTicks);