Text-to-CAD prompts that work
Every prompt below produced a file that passed dimensional checking. They are worth reading as patterns rather than copying verbatim: the structure is what makes them work.
The pattern
[what it is] + [overall size with units] + [each feature, with a diameter and a position]
That is the whole trick. Name the object, give it an envelope, then give every feature a size and a location. Anything you leave out is a number the tool has to invent.
Prompts and what they produced
| Prompt | Result | File |
|---|---|---|
| Mounting plate 120 x 80 mm with four 6 mm holes inset 10 mm from each corner | 120 × 80 mm | DXF |
| Mounting plate 200 x 100 mm with six 8 mm holes in two rows of three, inset 15 mm | 200 × 100 mm | DXF |
| Plate 150 x 100 mm with a 40 mm centre bore and four 8 mm corner holes inset 12 mm | 150 × 100 mm | DXF |
| Plate 100 x 100 mm with 12 mm rounded corners and a 30 mm centre hole | 100 × 100 mm | DXF |
| Electronics mounting plate 80 x 60 mm with four M3 clearance holes 3.4 mm inset 5 mm | 80 × 60 mm | DXF |
| Blind flange 100 mm outer diameter with six 11 mm bolt holes on an 80 mm bolt circle | 100 × 100 mm | DXF |
| Flange face 160 mm outer diameter, 80 mm centre bore, eight 14 mm bolt holes on a 125 mm bolt circle | 160 × 160 mm | DXF |
| Square flange 90 x 90 mm with a 50 mm centre bore and four 9 mm bolt holes inset 12 mm | 90 × 90 mm | DXF |
| Flange 250 mm outer diameter, 150 mm bore, twelve 18 mm bolt holes on a 200 mm bolt circle | 250 × 250 mm | DXF |
| Gasket 120 mm outer diameter, 80 mm inner diameter, six 8 mm bolt holes on a 100 mm bolt circle | 120 × 120 mm | DXF |
| Gasket 90 mm OD, 60 mm ID, eight 7 mm holes on a 75 mm bolt circle | 90 × 90 mm | DXF |
| Square gasket 100 x 100 mm with a 60 mm circular opening and four 6 mm corner holes inset 8 mm | 100 × 100 mm | DXF |
The full set is on the examples page.
Four phrasings that break it
Breaks A washer with a 20 mm radius
Works A washer with a 40 mm outer diameter
Radius and diameter confusion is the most common documented failure in text-to-CAD. State diameters. If you must use radius, say the word and check the result.
Breaks A bracket to hold a motor
Works An L-bracket, 60 mm base, 40 mm upright, 4 mm thick, four 5 mm holes
There is no such thing as a default motor. An underspecified request forces the tool to invent numbers, and invented numbers look exactly like real ones in a CAD file.
Breaks A plate about 100 mm across with some holes
Works A 100 × 100 mm plate with four 6 mm holes inset 12 mm from each corner
Every vague word becomes a guess. Corner inset is the dimension people forget most often, and it is the one that decides whether the part bolts up.
Breaks A 4 x 2 plate
Works A 4 inch by 2 inch plate, or 101.6 × 50.8 mm
Bare numbers get read in whatever unit the tool defaults to. Name the unit, or switch the unit toggle before generating.
When it should refuse
Ask for a 150 mm hole through a 100 mm plate and a good tool tells you that is impossible. Ask for something sculptural and it should tell you parametric CAD is the wrong tool rather than producing a lumpy approximation. If a tool silently returns geometry for either, that tells you what it does with your real requests too.
Try one
Paste any prompt above into the text to cad ai and compare what you get against the file linked next to it.
Open the tool