Searching a STL for RAMPS module on I3 acrylic

//change the next 6 lines to match your dimensions
dim=20;           //the width/height of the extrusion
wall=4;           //how thick you want the walls to be
height = 50;      //the length of the "sleeve"
hookwall = 6;     //how thick is the wall aroung the "hook" portion
hookdepth = 6;    //how wide is the aluminum over which the hook is hung
hookheight = 12;  //how long is the portion of the hook that overhangs the aluminum

//don't change below this point
dim2 = (dim/2+wall)*sin(45);

rotate([0, 90, 0])
difference() {
	union() {
		rotate([-45, 0, 0])
			translate([0, 0, height/2])
				cube([dim+wall*2, dim+wall*2, height], true);
		
		cube([dim+wall*2, dim2*2, dim2*4], true);
		translate([0, -dim2-(hookdepth+hookwall)/2, dim2])
			cube([dim+wall*2, hookdepth+hookwall, hookwall], true);
		translate([0, -dim2-hookwall/2-hookdepth, dim2+hookwall/2-hookdepth/2-hookheight/2])
			cube([dim+wall*2, hookwall, hookdepth+hookheight], true);
		
	}
	rotate([-45, 0, 0])
		translate([0, 0, height/2+wall])
			cube([dim, dim, height], true);

}