Aim

Design a functional object (a pencil box or a glasses stand) with correct dimensions, clearances, and wall thickness.

Requirements

• Ruler or measuring tape (a vernier caliper if available)

• Sketch paper, pencil, eraser, ruler/geometry box

• Computer with internet and a Tinkercad account

Step-by-Step Procedure

Part A — Plan from the Real World

1. Choose your object

   • Option 1: Pencil box (open-top or with a simple sliding lid)

   • Option 2: Glasses stand (a stable holder that supports the bridge and prevents tipping)

2. Measure the real items

   • For a pencil box: measure the longest pencil (typical ~175 mm), diameter (~7–8 mm), and how many pencils/erasers you want to store.

   • For a glasses stand: measure the overall width of the frame, bridge width (between lenses), and temple height where it rests.

   • Record all measurements in millimetres (mm).

3. Decide clearances and wall thickness

   • Clearance (extra room so parts fit) for boxes: +2–3 mm all around the inside.

   • Divider thickness or walls: 2–3 mm for basic strength (school prints; if just virtual, still use realistic values).

   • If designing a sliding lid, add +0.5–1.0 mm gap between sliding parts.

4. Sketch a dimensioned drawing

   • Draw a top view and a side view.

   • Mark internal dimensions (the usable space) and external dimensions (including walls).

   • For a pencil box with compartments, sketch divider positions and sizes.

5. Check proportions

   • Ask: Does the height look too tall for its width? Will it tip over?

   • Pencil box rule of thumb: height 40–60 mm is comfortable.

   • Glasses stand: wide base (e.g., base width ≥ 1.2 × frame width) to prevent tipping.

Part B — Build Precisely in Tinkercad

1. Set up the workspace

   • Open Tinkercad → Create New Design.

   • Bottom-right: set Units = millimetres.

   • Drag the Ruler onto the workplane (enables precise numeric sizing).

2. Make the base form

   • Drag a Box shape.

   • Enter external length × width × height from your sketch in the numeric fields.

3. Hollow the container (for a box)

   • Drag a Hole Box.

   • Size it to the internal length × width × depth (depth = total height – base thickness).

   • Center it inside the solid box (use Align tool), keep equal wall thickness all around.

   • Select both → Group to subtract and create a hollow box.

4. Add compartments (optional)

   • For dividers: add thin Box solids (thickness 2–3 mm) inside.

   • Use Align for neat placement.

   • Don’t Group with the hull until you’re happy with the layout.

5. Create a sliding lid (optional)

   • Add two thin rails along the top edges (solids ~2–3 mm thick).

   • Subtract matching Hole grooves in the lid or box, leaving 0.5–1.0 mm clearance.

   • Keep the lid a separate part so it can slide.

6. Design the glasses stand (alternative)

   • Base: a Box or rounded shape sized wider than the frame width (e.g., frame width + 20–30 mm).

   • Vertical support: a Box or cylinder rising from the base.

   • Nose/bridge cradle: a shallow U shape—combine a cylinder (Hole) to carve a curved slot in a small block.

   • Add a small lip to stop slipping (2–3 mm high).

7. Refine for comfort and safety

   • Round corners by using cylinders as Hole cuts, or use shape generators for fillets/chamfers.

   • Check all wall thicknesses: minimum 2 mm for strength.

8. Final checks

   • Use Measure (Ruler) to verify every critical size (internal space, divider spacing, rail gap).

   • Name and Save your design.

Design Checklist:

• Internal space fits the real item plus clearance.

• Wall thickness ≥ 2 mm everywhere.

• Base is wide enough to prevent tipping.

• Moving/sliding parts have 0.5–1.0 mm gap.

• All critical dimensions double-checked with the Ruler.