Most common reasons:
1. **The shape family isn't supported yet.** See the list above. If you typed "crown moulding" or "saddle" we don't have a recipe.
2. **You used imperial.** Everything is millimetres. "8 inches" → won't parse. Convert to mm first.
3. **Typo in a NACA code.** NACA codes are exactly 4 digits — `NACA2412`, not `NACA 2412` (a space is OK) or `NACA241` (3 digits).
4. **Missing keywords.** The parser looks for words like `chord`, `span`, `diameter`, `length`, `height` to figure out which number is which. If you type `NACA2412 200 600` we don't know which is chord and which is span. Add the keyword.
When it misses, the error message lists examples that DO work — copy one and adapt.
1. **The shape family isn't supported yet.** See the list above. If you typed "crown moulding" or "saddle" we don't have a recipe.
2. **You used imperial.** Everything is millimetres. "8 inches" → won't parse. Convert to mm first.
3. **Typo in a NACA code.** NACA codes are exactly 4 digits — `NACA2412`, not `NACA 2412` (a space is OK) or `NACA241` (3 digits).
4. **Missing keywords.** The parser looks for words like `chord`, `span`, `diameter`, `length`, `height` to figure out which number is which. If you type `NACA2412 200 600` we don't know which is chord and which is span. Add the keyword.
When it misses, the error message lists examples that DO work — copy one and adapt.