Luxury Car Electronic Shifter Modeling

// Automotive Electronic Gear Shift Knob
// Designed to match modern luxury electronic palm shifters (e.g. BYD / Audi style)

/* [Main Dimensions] */
knob_length = 82;        // Front-to-back length (mm)
knob_width = 52;         // Left-to-right grip width (mm)
knob_height = 80;        // Total vertical height (mm)
stem_diameter = 26;      // Base collar diameter (mm)
stem_height = 22;        // Base straight stem height (mm)

/* [Mounting Socket] */
mount_bore_d = 12.0;     // Shift rod diameter (mm)
mount_bore_depth = 34.0; // Socket depth (mm)
set_screw_d = 4.0;       // Grub screw hole diameter (mm)

/* [Options] */
include_set_screw = true;

/* [Smoothness] */
$fn = 48;

// True 4-corner rounded rectangle
module rounded_rect_2d(l, w, r) {
    dx = max(0.1, l/2 - r);
    dy = max(0.1, w/2 - r);
    hull() {
        translate([ dx,  dy]) circle(r = r, $fn = 36);
        translate([-dx,  dy]) circle(r = r, $fn = 36);
        translate([-dx, -dy]) circle(r = r, $fn = 36);
        translate([ dx, -dy]) circle(r = r, $fn = 36);
    }
}

module automotive_shift_knob() {
    difference() {
        // --- 1. SOLID COMBINED BODY ---
        union() {
            // A. Base stem collar
            cylinder(d = stem_diameter, h = stem_height);

            // B. Neck transition (smooth flare up to shifter head)
            hull() {
                translate([0, 0, stem_height - 1])
                    cylinder(d = stem_diameter, h = 1);
                translate([3, 0, stem_height + 14])
                    linear_extrude(height = 2)
                    rounded_rect_2d(46, 36, 14);
            }

            // C. Lower sculpted housing
            hull() {
                translate([3, 0, stem_height + 13])
                    linear_extrude(height = 2)
                    rounded_rect_2d(46, 36, 14);

                translate([2, 0, knob_height - 22])
                    linear_extrude(height = 2)
                    rounded_rect_2d(knob_length * 0.88, knob_width * 0.85, 16);

                translate([0, 0, knob_height - 14])
                    linear_extrude(height = 2)
                    rounded_rect_2d(knob_length * 0.96, knob_width * 0.94, 18);
            }

            // D. Chrome Bezel & Left Ergonomic Thumb Wing
            hull() {
                translate([0, 0, knob_height - 14])
                    linear_extrude(height = 2)
                    rounded_rect_2d(knob_length * 0.96, knob_width * 0.94, 18);

                translate([0, 0, knob_height - 9])
                    linear_extrude(height = 2)
                    rounded_rect_2d(knob_length, knob_width, 18);

                // Left thumb wing extension
                translate([0, -knob_width * 0.44, knob_height - 13])
                    scale([1.3, 0.7, 0.65])
                    sphere(r = 12);
            }

            // E. Top Glossy Pebble Insert
            hull() {
                translate([0.5, 0, knob_height - 8])
                    linear_extrude(height = 2)
                    rounded_rect_2d(knob_length * 0.84, knob_width * 0.80, 15);

                translate([1, 0, knob_height - 4])
                    linear_extrude(height = 1.5)
                    rounded_rect_2d(knob_length * 0.74, knob_width * 0.68, 13);

                translate([1.5, 0, knob_height - 1.5])
                    scale([knob_length * 0.30, knob_width * 0.24, 2.5])
                    sphere(r = 1);
            }

            // F. UNLOCK Button Pad (Smooth rounded thumb button)
            hull() {
                translate([8, -knob_width * 0.50, knob_height - 12.5])
                    sphere(r = 4.0);
                translate([-10, -knob_width * 0.50, knob_height - 13.5])
                    sphere(r = 4.0);
                translate([8, -knob_width * 0.44, knob_height - 8.5])
                    sphere(r = 3.5);
                translate([-10, -knob_width * 0.44, knob_height - 9.5])
                    sphere(r = 3.5);
            }

            // G. Embossed UNLOCK text integrated onto the button surface
            translate([-1, -knob_width * 0.53, knob_height - 13])
                rotate([90, 0, 0])
                linear_extrude(height = 1.2, center = true)
                text("UNLOCK", size = 3.2, font = "Liberation Sans:style=Bold", halign = "center", valign = "center");
        }

        // --- 2. SUBTRACTIONS & INTERFACES ---

        // Shift lever shaft hole
        translate([0, 0, -1])
            cylinder(d = mount_bore_d, h = mount_bore_depth + 1, $fn = 32);
        
        // Chamfered lead-in
        translate([0, 0, -0.1])
            cylinder(r1 = mount_bore_d/2 + 1.2, r2 = mount_bore_d/2, h = 1.5, $fn = 32);

        // Set screw tightening hole
        if (include_set_screw) {
            translate([0, 0, stem_height * 0.55])
                rotate([90, 0, 0])
                cylinder(d = set_screw_d, h = stem_diameter * 2, center = true, $fn = 24);
        }
    }
}

automotive_shift_knob();