module gcube(pos,rv=0,resv=1,rh=0)
{
  s = [ [1,1], [-1,1], [-1,-1], [1,-1] ];

  //-----  Vertical bevel (z axis)----------------------------------//

  //-- First stage: remove the corners
  difference() {
    cube(pos,center=true);

    //-- z-axis
    for (i=[0:3]) {
      translate( [s[i][0]*pos[0]/2, s[i][1]*pos[1]/2, 0] )
       cylinder(r=rv, h=pos[2]+10,center=true,$fn=4);
    }

    //-- x-axis
    for(i=[0:3]) {
      translate( [0,s[i][0]*pos[1]/2, s[i][1]*pos[2]/2] )
      rotate([0,90,0])
      cylinder(r=rh, h=pos[0]+10, center=true, $fn=4);
    }

    //-- y-axis
    *for(i=[0:3]) {
       translate( [s[i][1]*pos[0]/2,0,s[i][0]*pos[2]/2] )
       rotate([90,0,0])
       cylinder(r=rh, h=pos[0]+10, center=true, $fn=4);
    }

   }

  //-- Second stage: Add the cylinders in the corners
   for (i=[0:3]) {
    translate([s[i][0]*(pos[0]/2-rv),s[i][1]*(pos[1]/2-rv), 0])
    cylinder(r=rv, h=pos[2], center=true, $fn=4*resv);
  }

  //-- Horizontal Bevel --------------------------------- //
  


}

gcube([30,20,10],rv=1,rh=1,resv=5);