// Spacer Block based on engineering drawing
// All dimensions in millimeters (mm)

/* [Main Dimensions] */
block_length = 50;        // [20:1:100]
block_width = 30;         // [15:1:80]
block_height = 15;        // [5:1:50]

/* [Slot Dimensions] */
slot_width = 10;          // [2:1:40]
slot_depth = 5;           // [1:1:30]

/* [Hole Dimensions] */
hole_diameter = 4.5;      // [1:0.1:20]
hole_edge_offset_x = 10;  // [2:1:30]
hole_spacing_x = 30;      // [5:1:80]

/* [Appearance] */
block_color = "SteelBlue";

$fn = 64;

module spacer_block() {
    difference() {
        // Base block
        cube([block_length, block_width, block_height]);

        // Longitudinal central slot
        translate([-1, (block_width - slot_width) / 2, block_height - slot_depth])
            cube([block_length + 2, slot_width, slot_depth + 1]);

        // Through-holes
        // First hole (x = hole_edge_offset_x)
        translate([hole_edge_offset_x, block_width / 2, -1])
            cylinder(h = block_height + 2, d = hole_diameter);

        // Second hole (x = hole_edge_offset_x + hole_spacing_x)
        translate([hole_edge_offset_x + hole_spacing_x, block_width / 2, -1])
            cylinder(h = block_height + 2, d = hole_diameter);
    }
}

color(block_color)
spacer_block();