Example of multimaterial printing in OpenSCAD

// See https://en.wikibooks.org/wiki/OpenSCAD_User_Manual/Customizer

material = 0; // [0:all,1:mat1,2:mat2]

module assembly1()
  cube(1, center=true);

module assembly2()
  sphere(d=1.5, $fn=6);

module mat1()
  color("blue")
  difference() {
    assembly1();
    assembly2();
  }

module mat2()
  color("red")
  assembly2();

if (material == 0 || material == 1) mat1();
if (material == 0 || material == 2) mat2();