cadSet/text-to-cad/skills/cad/references/part-families/cup.md

Cup / mug reference

Read this file when the request is for a drinking vessel: cup, mug, water cup, tumbler, drinking cup, tea cup, coffee cup, handled cup, travel mug, 水杯, 杯子, 马克杯, or 茶杯.

This reference improves first-pass geometry structure only. It does not certify food safety, insulation, thermal performance, ergonomics, leak resistance, or manufacturability.

Recognition

Use this reference when the prompt describes a vessel whose primary geometry is an open container for liquid. Distinguish the common cases:

• cup / 水杯 / drinking cup: default open cup, usually without handle.
• mug / 马克杯 / handled cup: open cup with one handle on the side.
• tumbler: taller cup, optionally with a lid, usually without handle.
• travel mug: handled cup with a lid; may be an assembly if the lid is modeled.
• bottle: do not use this reference unless the user explicitly wants a cup-like bottle or bottle mug hybrid.

If the prompt does not mention a handle, do not add one by default.

Core invariants

A recognizable cup should have:

• An open top.
• A hollow interior cavity.
• A continuous side wall.
• A closed bottom.
• A continuous rim at the opening.
• A stable standing base or foot ring.

A handled mug should add:

• Exactly one main handle unless the prompt requests multiple handles.
• The handle mounted on one side of the cup body.
• Two attachment regions that intersect the cup body solidly.
• A clear gap between handle and cup body so the hand can pass through.
• A loop, C-shape, or arched form that reads as a graspable handle, not a fin, tab, rib, or broken bracket.

Default strategy

When the request is just cup or 水杯, generate a simple open cup with no handle:

• Revolved outer body.
• Hollow interior.
• Closed bottom.
• Slight outward taper or cylindrical wall.
• Small rim radius or lip.
• Optional foot ring.

When the request is mug, 马克杯, or handled cup, generate the same cup body plus one handle.

Handle strategy

The handle is the failure-prone part, so make it explicit:

• The handle must be a single continuous shape.
• It should attach to the cup body at two distinct points on the same side.
• The two attachment points should be vertically separated and usually near the upper-middle and lower-middle height of the cup.
• The handle should project outward far enough to create finger clearance, but not so far that it looks like a secondary looped part.
• The handle cross-section should be rounded or softly rectangular, not a thin blade.
• The handle opening should remain open; do not fill the inside of the loop with a solid web unless the prompt asks for a closed grip.
• Avoid multiple disconnected handle fragments, fins, or stray tabs.
• The handle should not attach at the rim edge only; it should engage the side wall with real thickness.

Required parameter roles

Use semantic parameters before modeling:

• height
• top_outer_diameter
• bottom_outer_diameter
• wall_thickness
• bottom_thickness
• inner_depth
• rim_radius
• rim_thickness
• foot_ring_diameter
• foot_ring_height
• handle_thickness
• handle_width
• handle_clearance
• handle_projection
• handle_attach_height_top
• handle_attach_height_bottom
• handle_attach_offset
• handle_loop_radius
• handle_loop_height

Only define the handle parameters when a handle is requested.

Feature roles to plan explicitly

• cup_body
• inner_cavity
• rim
• base
• foot_ring
• handle
• handle_attachment_upper
• handle_attachment_lower
• handle_clearance
• lid_seat or lid_interface if a lid is requested

Construction sequence

1. Build the cup body first using revolve or a smooth profile sweep.
2. Hollow the interior while preserving the bottom thickness.
3. Add the rim and optional foot ring.
4. If a handle is requested, place it on one side only.
5. Model the handle as one continuous loop or arched solid with two clear attachment zones.
6. Fuse the handle to the cup body so it reads as one coherent mug, not as a set of touching tabs.
7. Add a lid only if the prompt explicitly requests a covered container.
8. Apply final fillets/chamfers last.

For the handle, the tool or sweep profile should overshoot into the cup wall at both attachment regions. Avoid tangent-only contact.

Common failures to prevent

• Solid cup with no hollow interior.
• Cup with no bottom.
• Cup body turned into a bottle or vase shape when the prompt says cup.
• Handle omitted when the prompt says mug or handled cup.
• Handle added when the prompt only says cup or water cup.
• Handle split into two disconnected pieces.
• Handle as a tiny fin, tab, or shard instead of a loop.
• Handle attached only at the rim edge or at one point.
• Handle crossing through the cup cavity or cutting into the interior wall.
• Multiple handles unless explicitly requested.
• Lid generated when the prompt did not ask for one.

Validation targets

After generation, inspect or reason about:

• Opening is on top and remains open.
• Interior cavity exists and is connected to the opening.
• Bottom is closed and has nonzero thickness.
• Rim is continuous.
• If a handle exists, exactly one main handle is present.
• Handle has two attachment regions on the same side.
• Handle has sufficient clearance from the cup wall.
• Handle does not appear as a broken fragment or a separate brace.
• The model is a single connected solid unless a lid or travel-mug assembly is explicitly requested.