Create a cube with rounded sides

RoundedCube.scad

$fn=60;

// Answer from: https://stackoverflow.com/users/1320888/cutetare
// https://stackoverflow.com/questions/33146741/way-to-round-edges-of-objects-openscad/33289349#33289349
module roundedcube(xx, yy, height, radius) {

difference(){

    cube([xx,yy,height]);

    difference(){
        translate([-.5,-.5,-.2])
        cube([radius+.5,radius+.5,height+.5]);

        translate([radius,radius,height/2])
        cylinder(height,radius,radius,true);
    }
    translate([xx,0,0])
    rotate(90)
    difference(){
        translate([-.5,-.5,-.2])
        cube([radius+.5,radius+.5,height+.5]);

        translate([radius,radius,height/2])
        cylinder(height,radius,radius,true);
    }

    translate([xx,yy,0])
    rotate(180)
    difference(){
        translate([-.5,-.5,-.2])
        cube([radius+.5,radius+.5,height+.5]);

        translate([radius,radius,height/2])
        cylinder(height,radius,radius,true);
    }

    translate([0,yy,0])
    rotate(270)
    difference(){
        translate([-.5,-.5,-.2])
        cube([radius+.5,radius+.5,height+.5]);

        translate([radius,radius,height/2])
        cylinder(height,radius,radius,true);
    }
}
}

// Simpler code with same result
module roundedcube2(xx, yy, height, radius)
{
    translate([0,0,height/2])
    hull()
    {
        translate([radius,radius,0])
        cylinder(height,radius,radius,true);

        translate([xx-radius,radius,0])
        cylinder(height,radius,radius,true);

        translate([xx-radius,yy-radius,0])
        cylinder(height,radius,radius,true);

        translate([radius,yy-radius,0])
        cylinder(height,radius,radius,true);
    }
}


roundedcube(20, 30, 50, 5);
translate([30,0,0])
roundedcube2(20, 30, 50, 5);

Here's my suggestion to add the center feature that normal cube() has (Plus centerxy, since that seems to be needed often)

module roundedcube(xx, yy, height, radius, center=false, centerxy=false)
{
    translate([(center||centerxy)?-xx/2:0,(center||centerxy)?-yy/2:0,center?0:height/2])
    hull()
    {
        translate([radius,radius,0])
        cylinder(height,radius,radius,true);

        translate([xx-radius,radius,0])
        cylinder(height,radius,radius,true);

        translate([xx-radius,yy-radius,0])
        cylinder(height,radius,radius,true);

        translate([radius,yy-radius,0])
        cylinder(height,radius,radius,true);
    }
}