Writing good prompts

How to write a prompt that yields a manufacturable model.

Writing good prompts

The model rewards specificity. Vague prompts produce vague geometry.

What to include

  • Function: what does the part do?
  • Envelope: bounding-box dimensions in mm or in.
  • Interfaces: how does it mate with adjacent parts? Bolt pattern, slot, snap-fit?
  • Material & process: SLA, FDM, CNC aluminum, sheet-metal, injection-molded?
  • Constraints: wall thickness, draft angle, minimum hole diameter.

Examples

A 60×40×12 mm sheet-metal L-bracket in 2 mm stainless. Two M5 clearance holes on each face on a 40 mm pitch. Bend radius 3 mm.

A snap-fit lid for a 92×62×24 mm enclosure. PLA, 1.8 mm walls, four cantilever snaps along the long sides with 0.5 mm deflection.

The more your prompt reads like a machinist’s note, the better the output.