tier-2-hex-bolt / gemini-2.5-flash-lite

  // M8 Hex Bolt (shank only, no threads)
  
  // Bolt dimensions
  head_across_flats = 13; // Across-flats of the hex head
  head_height = 5.3;     // Height of the hex head
  shank_diameter = 8;    // Diameter of the shank
  shank_length = 30;     // Length of the shank
  
- // Calculate hex head radius and outer radius for minkowski
- head_radius = head_across_flats / 2;
- hex_outer_radius = head_radius / cos(30); // Radius to the vertex of the hexagon
+ // Calculate the radius to the vertices of the hexagon from the center
+ hex_radius_to_vertex = head_across_flats / 2 / cos(30);
  
- // Create the hex head
+ // Create the hex head using polygon and linear_extrude
  module hex_head() {
-     hull() {
-         // Create 6 points of the hexagon at the base
-         for (i = [0:6]) {
-             rotate([0, 0, i * 60]) {
-                 translate([head_radius, 0, 0]) {
-                     cylinder(h=head_height, r=0.1, center=false); // Small cylinder to define points
-                 }
-             }
-         }
+     linear_extrude(height = head_height) {
+         polygon(points = [
+             [hex_radius_to_vertex * cos(0), hex_radius_to_vertex * sin(0)],
+             [hex_radius_to_vertex * cos(60), hex_radius_to_vertex * sin(60)],
+             [hex_radius_to_vertex * cos(120), hex_radius_to_vertex * sin(120)],
+             [hex_radius_to_vertex * cos(180), hex_radius_to_vertex * sin(180)],
+             [hex_radius_to_vertex * cos(240), hex_radius_to_vertex * sin(240)],
+             [hex_radius_to_vertex * cos(300), hex_radius_to_vertex * sin(300)]
+         ]);
      }
  }
  
  // Create the shank
  module shank() {
      cylinder(h=shank_length, r=shank_diameter/2, center=false);
  }
  
  // Assemble the bolt
  module m8_bolt() {
      // Place the hex head at the origin (z=0)
-     // The hex_head module creates its base at z=0 by default
+     // The hex_head is created with its base at z=0 by default.
      hex_head();
  
-     // Place the shank below the head, extending in the -Z direction
-     // The hex head is at z=0 to head_height. The shank starts at z=0 and goes down.
-     // So we need to translate the shank by head_height in the negative Z direction
+     // Place the shank below the head, extending in the -Z direction.
+     // The head's bottom face is at z=0. So the shank should start from z=0 downwards.
      translate([0, 0, -head_height]) {
          shank();
      }
  }
  
  // Render the bolt
  m8_bolt();

  // M8 Hex Bolt (shank only, no threads)
  
  // Bolt dimensions
  head_across_flats = 13; // Across-flats of the hex head
  head_height = 5.3;     // Height of the hex head
  shank_diameter = 8;    // Diameter of the shank
  shank_length = 30;     // Length of the shank
  
  // Calculate the radius to the vertices of the hexagon from the center
- hex_radius_to_vertex = head_across_flats / 2 / cos(30);
+ // The distance from the center to the midpoint of a side (apothem) is
+ // half the across-flats distance. The distance to a vertex is
+ // apothem / cos(30 degrees).
+ hex_radius_to_vertex = (head_across_flats / 2) / cos(30);
  
  // Create the hex head using polygon and linear_extrude
  module hex_head() {
+     // The polygon is defined in the XY plane, and linear_extrude extrudes it along Z.
+     // By default, the extrusion starts from z=0 and goes up.
      linear_extrude(height = head_height) {
          polygon(points = [
              [hex_radius_to_vertex * cos(0), hex_radius_to_vertex * sin(0)],
              [hex_radius_to_vertex * cos(60), hex_radius_to_vertex * sin(60)],
              [hex_radius_to_vertex * cos(120), hex_radius_to_vertex * sin(120)],
              [hex_radius_to_vertex * cos(180), hex_radius_to_vertex * sin(180)],
              [hex_radius_to_vertex * cos(240), hex_radius_to_vertex * sin(240)],
              [hex_radius_to_vertex * cos(300), hex_radius_to_vertex * sin(300)]
          ]);
      }
  }
  
  // Create the shank
  module shank() {
+     // The cylinder is created with its base at z=0 and extends upwards.
+     // To make it extend in the -Z direction, we'll negate its height or translate it.
      cylinder(h=shank_length, r=shank_diameter/2, center=false);
  }
  
  // Assemble the bolt
  module m8_bolt() {
-     // Place the hex head at the origin (z=0)
-     // The hex_head is created with its base at z=0 by default.
+     // Place the hex head. Its bottom face is at z=0 as per the prompt.
      hex_head();
  
-     // Place the shank below the head, extending in the -Z direction.
-     // The head's bottom face is at z=0. So the shank should start from z=0 downwards.
-     translate([0, 0, -head_height]) {
-         shank();
+     // Place the shank below the head.
+     // The head's bottom is at z=0. The shank should start from z=0 and go downwards.
+     // To achieve this, we translate the shank module's default position.
+     // The shank module creates a cylinder starting at z=0 and going up.
+     // We need to move it down by the height of the head and then negate its Z extent,
+     // or simply translate it so its top face aligns with the head's bottom face.
+     // A simpler way is to translate it by -head_height and then reverse its orientation if needed,
+     // or by creating it with a negative height if OpenSCAD supported that directly for cylinder.
+     // The current shank() creates a cylinder from z=0 to z=shank_length.
+     // To place it below the head (which is from z=0 to z=head_height),
+     // we need its top at z=0 and extend to z=-shank_length.
+     // So we translate it by (0, 0, -head_height). This moves the base of the cylinder to z = -head_height.
+     // The cylinder then goes from z = -head_height to z = -head_height + shank_length.
+     // This is incorrect.
+ 
+     // Let's re-think the placement.
+     // Head is from z=0 to z=head_height.
+     // Shank needs to be from z=0 downwards.
+     // The shank module currently creates a cylinder from z=0 to z=shank_length.
+     // We need to flip it and position its top at z=0.
+ 
+     // Option 1: Create shank that extends downwards directly.
+     // module shank_down() {
+     //     cylinder(h=-shank_length, r=shank_diameter/2, center=false); // This would require negative height support
+     // }
+     // translate([0, 0, 0]) shank_down(); // This would put its top at z=0.
+ 
+     // Option 2: Use translate and rotate or scale.
+     // Create the shank normally (z=0 to shank_length) and then move it.
+     // We want the top of the shank to be at z=0. The shank module's top is at z=shank_length.
+     // So we need to move it up by shank_length, and then flip it.
+     // Or, we create it and then move its base to z=0 and then flip its Z direction.
+ 
+     // The simplest is to align the top of the shank with the bottom of the head.
+     // The head's bottom is at z=0.
+     // The shank module creates a cylinder from z=0 to z=shank_length.
+     // We want the shank to go from z=0 to z=-shank_length.
+     // So we need to translate the shank module by (0, 0, 0) but with a negative height, which we cannot do directly.
+     // A common way is to center the cylinder and then translate.
+     // If cylinder(h=..., r=..., center=true), it goes from -h/2 to +h/2.
+ 
+     // Let's go back to the original intent: "shankは z<0 側へ伸ばす" and "頭部の底面が原点(z=0)に来るように配置".
+     // The hex_head() call already places the head with its bottom at z=0.
+     // So the shank should start at z=0 and go down.
+     // The current shank() creates a cylinder from z=0 to z=shank_length.
+     // We need to take this cylinder and move its top face (which is at z=shank_length) to z=0.
+     // This means translating it upwards by -shank_length.
+     // This is incorrect.
+ 
+     // Let's try again.
+     // Head: z = 0 to z = head_height.
+     // Shank: Needs to be from z = 0 to z = -shank_length.
+ 
+     // Current shank() makes cylinder from z=0 to z=shank_length.
+     // To make it go from z=0 to z=-shank_length, we can do the following:
+     // 1. Translate it up so its base is at z = shank_length.
+     // 2. Then flip it along the Z axis.
+     // 3. Then translate it down so its top is at z=0.
+ 
+     // Let's use a more direct approach.
+     // We want the top of the shank to be at z=0.
+     // The shank module creates a cylinder with its base at z=0.
+     // So, if we translate it by (0, 0, -shank_length), its base is at z=-shank_length and top at z=0.
+     // This is correct for positioning its top at z=0.
+     // However, the prompt states "シャンクは z<0 側へ伸ばす", meaning it should extend into negative Z.
+     // So, the bottom of the shank should be at z=-shank_length and the top at z=0.
+ 
+     // The hex_head() is called and its bottom is at z=0.
+     // The shank should then start from z=0 and go to z=-shank_length.
+     // The shank module currently creates a cylinder from z=0 to z=shank_length.
+     // To make it go from z=0 to z=-shank_length, we need to reverse its direction.
+     // One way is to create the cylinder and then rotate it 180 degrees around X or Y,
+     // then translate it.
+ 
+     // A simpler way is to realize that OpenSCAD's cylinder(h, r) creates from z=0 to z=h.
+     // If we want it from z=0 to z=-shank_length, we can write:
+     // translate([0,0,0]) {
+     //     rotate([180, 0, 0]) cylinder(h=shank_length, r=shank_diameter/2, center=false);
+     // }
+     // This places the origin of the rotated cylinder at z=0, so it will go from z=0 down to z=-shank_length.
+ 
+     // So, the shank should be placed at z=0 (origin of the rotated cylinder).
+     translate([0, 0, 0]) {
+         rotate([180, 0, 0]) {
+             cylinder(h=shank_length, r=shank_diameter/2, center=false);
+         }
      }
  }
  
  // Render the bolt
  m8_bolt();

  // M8 Hex Bolt (shank only, no threads)
  
  // Bolt dimensions
  head_across_flats = 13; // Across-flats of the hex head
  head_height = 5.3;     // Height of the hex head
  shank_diameter = 8;    // Diameter of the shank
  shank_length = 30;     // Length of the shank
  
  // Calculate the radius to the vertices of the hexagon from the center
  // The distance from the center to the midpoint of a side (apothem) is
  // half the across-flats distance. The distance to a vertex is
  // apothem / cos(30 degrees).
  hex_radius_to_vertex = (head_across_flats / 2) / cos(30);
  
  // Create the hex head using polygon and linear_extrude
  module hex_head() {
      // The polygon is defined in the XY plane, and linear_extrude extrudes it along Z.
      // By default, the extrusion starts from z=0 and goes up.
      linear_extrude(height = head_height) {
          polygon(points = [
              [hex_radius_to_vertex * cos(0), hex_radius_to_vertex * sin(0)],
              [hex_radius_to_vertex * cos(60), hex_radius_to_vertex * sin(60)],
              [hex_radius_to_vertex * cos(120), hex_radius_to_vertex * sin(120)],
              [hex_radius_to_vertex * cos(180), hex_radius_to_vertex * sin(180)],
              [hex_radius_to_vertex * cos(240), hex_radius_to_vertex * sin(240)],
              [hex_radius_to_vertex * cos(300), hex_radius_to_vertex * sin(300)]
          ]);
      }
  }
  
  // Create the shank
  module shank() {
      // The cylinder is created with its base at z=0 and extends upwards.
-     // To make it extend in the -Z direction, we'll negate its height or translate it.
-     cylinder(h=shank_length, r=shank_diameter/2, center=false);
+     // To make it extend in the -Z direction from z=0, we rotate it 180 degrees around the X axis.
+     // This makes the "top" (originally at h) be at z=0, and the "bottom" (originally at z=0) be at z=-h.
+     translate([0, 0, 0]) { // Align the top of the rotated cylinder with z=0
+         rotate([180, 0, 0]) {
+             cylinder(h=shank_length, r=shank_diameter/2, center=false);
+         }
+     }
  }
  
  // Assemble the bolt
  module m8_bolt() {
      // Place the hex head. Its bottom face is at z=0 as per the prompt.
      hex_head();
  
      // Place the shank below the head.
-     // The head's bottom is at z=0. The shank should start from z=0 and go downwards.
-     // To achieve this, we translate the shank module's default position.
-     // The shank module creates a cylinder starting at z=0 and going up.
-     // We need to move it down by the height of the head and then negate its Z extent,
-     // or simply translate it so its top face aligns with the head's bottom face.
-     // A simpler way is to translate it by -head_height and then reverse its orientation if needed,
-     // or by creating it with a negative height if OpenSCAD supported that directly for cylinder.
-     // The current shank() creates a cylinder from z=0 to z=shank_length.
-     // To place it below the head (which is from z=0 to z=head_height),
-     // we need its top at z=0 and extend to z=-shank_length.
-     // So we translate it by (0, 0, -head_height). This moves the base of the cylinder to z = -head_height.
-     // The cylinder then goes from z = -head_height to z = -head_height + shank_length.
-     // This is incorrect.
- 
-     // Let's re-think the placement.
-     // Head is from z=0 to z=head_height.
-     // Shank needs to be from z=0 downwards.
-     // The shank module currently creates a cylinder from z=0 to z=shank_length.
-     // We need to flip it and position its top at z=0.
- 
-     // Option 1: Create shank that extends downwards directly.
-     // module shank_down() {
-     //     cylinder(h=-shank_length, r=shank_diameter/2, center=false); // This would require negative height support
-     // }
-     // translate([0, 0, 0]) shank_down(); // This would put its top at z=0.
- 
-     // Option 2: Use translate and rotate or scale.
-     // Create the shank normally (z=0 to shank_length) and then move it.
-     // We want the top of the shank to be at z=0. The shank module's top is at z=shank_length.
-     // So we need to move it up by shank_length, and then flip it.
-     // Or, we create it and then move its base to z=0 and then flip its Z direction.
- 
-     // The simplest is to align the top of the shank with the bottom of the head.
-     // The head's bottom is at z=0.
-     // The shank module creates a cylinder from z=0 to z=shank_length.
-     // We want the shank to go from z=0 to z=-shank_length.
-     // So we need to translate the shank module by (0, 0, 0) but with a negative height, which we cannot do directly.
-     // A common way is to center the cylinder and then translate.
-     // If cylinder(h=..., r=..., center=true), it goes from -h/2 to +h/2.
- 
-     // Let's go back to the original intent: "shankは z<0 側へ伸ばす" and "頭部の底面が原点(z=0)に来るように配置".
-     // The hex_head() call already places the head with its bottom at z=0.
-     // So the shank should start at z=0 and go down.
-     // The current shank() creates a cylinder from z=0 to z=shank_length.
-     // We need to take this cylinder and move its top face (which is at z=shank_length) to z=0.
-     // This means translating it upwards by -shank_length.
-     // This is incorrect.
- 
-     // Let's try again.
-     // Head: z = 0 to z = head_height.
-     // Shank: Needs to be from z = 0 to z = -shank_length.
- 
-     // Current shank() makes cylinder from z=0 to z=shank_length.
-     // To make it go from z=0 to z=-shank_length, we can do the following:
-     // 1. Translate it up so its base is at z = shank_length.
-     // 2. Then flip it along the Z axis.
-     // 3. Then translate it down so its top is at z=0.
- 
-     // Let's use a more direct approach.
-     // We want the top of the shank to be at z=0.
-     // The shank module creates a cylinder with its base at z=0.
-     // So, if we translate it by (0, 0, -shank_length), its base is at z=-shank_length and top at z=0.
-     // This is correct for positioning its top at z=0.
-     // However, the prompt states "シャンクは z<0 側へ伸ばす", meaning it should extend into negative Z.
-     // So, the bottom of the shank should be at z=-shank_length and the top at z=0.
- 
-     // The hex_head() is called and its bottom is at z=0.
-     // The shank should then start from z=0 and go to z=-shank_length.
-     // The shank module currently creates a cylinder from z=0 to z=shank_length.
-     // To make it go from z=0 to z=-shank_length, we need to reverse its direction.
-     // One way is to create the cylinder and then rotate it 180 degrees around X or Y,
-     // then translate it.
- 
-     // A simpler way is to realize that OpenSCAD's cylinder(h, r) creates from z=0 to z=h.
-     // If we want it from z=0 to z=-shank_length, we can write:
-     // translate([0,0,0]) {
-     //     rotate([180, 0, 0]) cylinder(h=shank_length, r=shank_diameter/2, center=false);
-     // }
-     // This places the origin of the rotated cylinder at z=0, so it will go from z=0 down to z=-shank_length.
- 
-     // So, the shank should be placed at z=0 (origin of the rotated cylinder).
-     translate([0, 0, 0]) {
-         rotate([180, 0, 0]) {
-             cylinder(h=shank_length, r=shank_diameter/2, center=false);
-         }
-     }
+     // The shank module is designed to extend in the -Z direction from z=0.
+     shank();
  }
  
  // Render the bolt
  m8_bolt();