About this 3D model

module carrito() { $fn = 90; rotate(270, [0, 1, 0]) translate ([12.5,0,0]) difference (){ //main cube; translate ([-12.5,-55,-2]) cube ([12.5,110,52]); //hueco pa caja de bolas IZQUIERDA; translate ([-13,-40,35]) rotate(90, [0, 1, 0]) cylinder (h=7,r=11); translate ([-13,-40,35]) rotate(90, [0, 1, 0]) cylinder (h=20,r=9.5); //hueco pa caja de bolas DERECHA; translate ([-13,40,35]) rotate(90, [0, 1, 0]) cylinder (h=7,r=11); translate ([-13,40,35]) rotate(90, [0, 1, 0]) cylinder (h=20,r=9.5); //lineal rollers 80mm center to center; translate ([0,40,0]) cylinder(h = 24, r= 7.5); translate ([0,-40,0]) cylinder(h = 24, r= 7.5); //passthrough roller holes; translate ([0,40,-2]) cylinder(h = 60, r= 5); translate ([0,-40,-2]) cylinder(h = 60, r= 5); //ziptie holes left; translate ([-12.5,-52,3]) cube ([12.5,2,5]); translate ([-12.5,-52,16]) cube ([12.5,2,5]); translate ([-12.5,-30,3]) cube ([12.5,2,5]); translate ([-12.5,-30,16]) cube ([12.5,2,5]); //ziptie holes right; translate ([-12.5,50,3]) cube ([12.5,2,5]); translate ([-12.5,50,16]) cube ([12.5,2,5]); translate ([-12.5,28,3]) cube ([12.5,2,5]); translate ([-12.5,28,16]) cube ([12.5,2,5]); //center square hole; translate ([-12.5,-25,30]) cube ([12.5,50,20]); //apretador de caja de bola IZQUIERDA; translate ([-13,-41,40]) cube ([12.5,2,10]); //apretador de caja de bola DERECHA; translate ([-13,39,40]) cube ([12.5,2,10]); //tornillo de apretar la caja de bola; translate ([-9,56,47.5]) rotate(90, [1,0,0]) cylinder (h=112,r=1.5); } } carrito();