chessboard.openscad

// パラメータ
square_size = 40; // マス目の大きさ (mm)
board_size = 4; // チェス盤の大きさ (8x8)
thick = 10;

hole_width = 100;
hole_height = 5;
hole_depth = 5;

difference () {
    difference () {
        // base
        cube([square_size * board_size, square_size * board_size, thick]);
        // edges
        for (i = [0 : board_size - 1]) {
            for (j = [0 : board_size - 1]) {
                if ((i + j) % 2 == 0) {
                    translate([i * square_size, j * square_size, 0]) {
                        intersection () {
                            translate([0, 0, thick - 1.5])
                                cube([square_size, square_size, 1.5]);
                            translate([square_size, square_size, thick])
                                rotate([90, 180, 0])
                                    linear_extrude(height = square_size)
                                        polygon(points = [[0, 0], [square_size, 0], [square_size / 2, square_size / 2]]);
                            translate([0, square_size, thick])
                                rotate([90, 180, 90])
                                    linear_extrude(height = square_size)
                                        polygon(points = [[0, 0], [square_size, 0], [square_size / 2, square_size / 2]]);
                        }
                    }
                }
            }
        }
    }
    // hole
    translate([(square_size * board_size - hole_width - 0.5) / 2, 0, (thick - hole_height - 0.5) / 2])
        cube([hole_width + 0.5, hole_depth + 0.5, hole_height + 0.5]);
}

// ratch
translate([-hole_depth, (square_size * board_size - hole_width) / 2, (thick - hole_height) / 2])
    cube([hole_depth, hole_width, hole_height]);