iter-png-1/gpt-5.4-nano / tier-2-offset-handle-mug

```openscad
// Mug + +X side D-handle (OpenSCAD)
// Dimensions (mm):
// Mug: outer Ø80, inner Ø70 (wall 5), height 90, bottom thickness 6
// Handle: only on +X side, D-shape (outer half-cylinder with flat inner side),
// inner void ~ 30 (height) x 25 (width in Y). Positioned around middle of mug height.

$fn = 128;

// ---- Mug parameters ----
outer_d = 80;
inner_d = 70;
t_wall  = (outer_d - inner_d)/2; // 5
h_mug   = 90;
t_bottom= 6;

mug_outer_r = outer_d/2;
mug_inner_r = inner_d/2;

// ---- Handle parameters ----
handle_void_w = 25;   // width in Y (requested)
handle_void_h = 30;   // height in Z (requested)

handle_center_z = h_mug/2;

// Handle grip depth along +X (how far it extends from the mug)
handle_depth = 20;

// Handle wall thickness (for D shell)
handle_wall = 4;

// How much extra overlap to avoid manifold gaps
overlap = 0.6;

// For D-shape outer half-circle radius in YZ:
r_outer = handle_void_h/2 + handle_wall;   // gives outer size; inner will be r_inner = r_outer-handle_wall
r_inner = r_outer - handle_wall;

// Mug contact plane for handle:
x_mug_outer = mug_outer_r; // x = +40 touches outer wall

// Small helper: 2D half-circle polygon (Y-Z plane) with flat at Y=0
module half_circle_2d(r=10, yflip=false) {
  // Creates points for a semicircle in +Y direction, from Z=-r..+r, with Y>=0
  pts = [
    for (i=[0:64])
      let(
        a = -90 + i*(180/64),
        y = r*cos(a),   // cos maps -90..+90 -> 0..r..0
        z = r*sin(a)    // sin maps -90..+90 -> -r..+r
      )
      [yflip ? -y : y, z]
  ];
  // Close with flat edge on Y=0 (connect ends)
  polygon(concat(pts, [[0,-r],[0,r]]));
}

// Build D-shaped handle as an extrusion along X (depth).
// D is defined in YZ cross-section:
// - Outer: semicircle (Y>=0) with flat at Y=0
// - Inner void: smaller semicircle (Y>=0) with flat at Y=0
// Then we clip in Y (width) to ~handle_void_w and in Z to ~handle_void_h.
module handle_d() {

  // Cross-section extents:
  // We'll clip the D in Y to control void width.
  // Our semicircle is centered at Y=0; flat at Y=0 implies curved bulges toward +Y.
  // For inner void width ~25, we clip y from 0..(handle_void_w).
  clip_y_max = handle_void_w; // void width along Y

  // For Z we center at handle_center_z with requested height
  z0 = handle_center_z - handle_void_h/2;
  z1 = handle_center_z + handle_void_h/2;

  // Outer half-circle in YZ plane, extruded along +X.
  // We position the flat face at Y=0 and place the semicircle bulge toward +Y.
  difference() {
    // Outer handle (D shell)
    translate([x_mug_outer - overlap, 0, 0])
      linear_extrude(height=handle_depth, center=false)
        translate([0,0,0]) // already in YZ in 2D
          intersection() {
            half_circle_2d(r=r_outer, yflip=false);
            // Clip to achieve target void width/shape (keep only y in [0..clip_y_max])
            // and allow enough thickness above/below due to wall thickness.
            // We'll clip in the 2D stage by intersecting with a rectangle.
            translate([0,0])
              square([clip_y_max, 2*r_outer + 1], center=false);
          }

    // Inner void: subtract a smaller D (so wall remains)
    translate([x_mug_outer - overlap, 0, 0])
      // Move inner void so its Z span is centered correctly
      translate([0,0,0])
      linear_extrude(height=handle_depth + 2*overlap, center=false)
        intersection() {
          // Smaller half-circle
          half_circle_2d(r=r_inner, yflip=false);
          // Clip in Y to target width:
          square([clip_y_max, 2*r_inner + 1], center=false);
        }

    // Finally clip inner void in Z to exact requested height by subtracting a 3D box
    // (easier than precise 2D Z offsets).
    translate([x_mug_outer - overlap - 0.5, 0, z0])
      cube([handle_depth + 2*overlap + 1, clip_y_max, handle_void_h], center=false);
  }
}

// Place handle so its flat face is toward mug center (i.e., at Y=0 plane).
// Requirement: attach only to +X side, and connect to mug outer wall.
// We'll also ensure it doesn't appear on -X.
module mug_with_handle() {
  union() {
    // Mug body: outer cylinder minus inner cavity, leaving bottom thickness.
    difference() {
      cylinder(d=outer_d, h=h_mug, center=false);
      translate([0,0,t_bottom])
        cylinder(d=inner_d, h=h_mug - t_bottom, center=false);
    }

    // Handle: build D handle shell and clip in X to ensure only +X attachment.
    // Position so D is centered at mug's middle height.
    translate([0,0,0]) {
      // The handle_d() is centered around handle_center_z by subtractive Z box,
      // but its outer half-cylinder extrusion exists from Z=-r_outer..+r_outer around origin.
      // So we shift Z of the whole handle to mug center.
      translate([0,0,handle_center_z]) {
        // Our handle_d() expects Z clipping box at absolute z0..z1 in mug coords,
        // so we implement by shifting handle_z logic inside handle_d via absolute z0/z1
        // already computed. Thus set origin accordingly: handle_d includes absolute z0/z1
        // but we are shifting; to avoid double-shift, redefine approach:
        // We'll implement a dedicated shifted handle below (simpler).

      }
    }
  }
}

// Dedicated handle with correct Z placement (no double-shift):
module handle_d_placed() {
  clip_y_max = handle_void_w;
  // Z limits in absolute coordinates of mug
  z0 = handle_center_z - handle_void_h/2;

  // We'll create outer and inner D extrusions centered around Z=0,
  // then shift to z0 appropriately using linear_extrude base at Z=-r_outer.
  // Since half_circle_2d spans Z in [-r_outer, +r_outer] (in 2D), shifting by handle_center_z
  // will put the Z center at handle_center_z.
  difference() {
    // Outer
    translate([x_mug_outer - overlap, 0, handle_center_z])
      linear_extrude(height=handle_depth, center=false)
        intersection() {
          half_circle_2d(r=r_outer, yflip=false);
          square([clip_y_max, 2*r_outer + 1], center=false);
        }

    // Inner: smaller D
    translate([x_mug_outer - overlap, 0, handle_center_z])
      linear_extrude(height=handle_depth + 2*overlap, center=false)
        intersection() {
          half_circle_2d(r=r_inner, yflip=false);
          square([clip_y_max, 2*r_inner + 1], center=false);
        }

    // Ensure inner void height is exactly handle_void_h
    // (Also prevents the inner D from exceeding requested vertical size.)
    translate([x_mug_outer - overlap - 0.5, 0, z0])
      cube([handle_depth + 2*overlap + 1, clip_y_max, handle_void_h], center=false);
  }
}

module mug_with_handle_fixed() {
  union() {
    difference() {
      cylinder(d=outer_d, h=h_mug, center=false);
      translate([0,0,t_bottom])
        cylinder(d=inner_d, h=h_mug - t_bottom, center=false);
    }
    // Add handle only on +X side
    handle_d_placed();
  }
}

mug_with_handle_fixed();
```