partforge

Extrusion 2020 end cap

hard tier · create

The request

Make an end cap for 20 mm square aluminium extrusion. A 20 mm square cap plate, 3 mm thick, lying flat in the XY plane, centred on the origin in X and Y, its bottom face on Z = 0 and its top face at Z = 3, Z up. A round plug 6.8 mm in diameter and 8 mm long stands up from the centre of the top face, to press into the extrusion's 7 mm centre bore. No holes. Name the sub-part exactly `cap`.

What the AI judge checks

  • A small square plate
  • A single round plug standing up from the centre of the plate
  • The plug is clearly longer than the plate is thick
  • No holes anywhere in the cap

Measured checks

  • one sub-part named cap (gate)
  • cap is 20 × 20 and 11 mm tall overall
  • plug is 6.8 mm in diameter
  • plate is 3 mm thick at a corner
  • nothing stands on the plate except the plug (gate)

Ranked by hand

One reviewer put one attempt from each model in order, best first, ties left tied.

  1. #1 tie
    Gemini 3.8 Flash
    Gemini 3.8 Flash's ranked attempt
  2. #1 tie
    GPT-5.6 Sol
    GPT-5.6 Sol's ranked attempt
  3. #1 tie
    GPT-6 Astra
    GPT-6 Astra's ranked attempt
  4. #1 tie
    Opus 5
    Opus 5's ranked attempt
  5. #1 tie
    Fable 5.1
    Fable 5.1's ranked attempt

Ordering by hand decides Human rank and Human rate on the leaderboard; it never affects Overall or Strict.

Every model's attempts

Run baseline-2026-092026-09-10commit 41aec7daspend $339.70 + $48.02 AI judging, 7 unpricedOther runs: 2026-09-04T20-02-10-stage2-hard-cases, 2026-09-04T19-48-31-screen-14-fixed