Named dimensions A, B, C and a dimension table on your drawing
Many part drawings do not write numbers on the dimensions at all. They use letters — A, B, C — and a table beside the drawing says A = 22.1 MAX, B = 12.5 ± 0.3. You see this a lot on spec drawings for electronic components, coils, transformers and inspection drawings. DXCAD2D Online names dimensions for you and builds a dimension table that keeps itself up to date.
Why letters instead of numbers?
- One drawing, many sizes. Parts with the same shape in different sizes — five coil variants, say — share one picture; only the table changes.
- Easier QC. Inspection records refer to the same letters as the drawing, with no need to describe where each measurement is.
- A cleaner drawing. Long tolerances such as 12.50 +0.10/−0.05 go in the table instead of crowding the picture.
- Matches customer specs. Many customers already send specs as an A–F table; a drawing in the same form is quicker to check.
Steps in DXCAD2D Online
- Open DXCAD2D Online, draw the part and dimension it as usual with D (press Tab while placing to switch between horizontal, vertical and aligned).
- Select the dimensions to name in the order you want them to become A, B, C — click the first, then Shift+click the next.
- In the properties panel on the right, click Name A, B, C… in the order picked. The dimensions now show letters instead of values.
- Click Insert / update the dimension table. The table appears beside the drawing:
UNIT : mmon the first line, thenA = …in letter order. - Move the table where you want it with M.
Tolerances and table values
Select one dimension at a time and the panel shows these fields:
| Field | What it does | Example |
|---|---|---|
| Dimension name (shown instead of the value) | Set or change the name yourself; it need not be a single letter | A, B, H1, Ø |
| Value in the table | The value printed in the table; left empty, the measured value is used | 22.1 |
| Tolerance / note | Added after the value in the table | ± 0.3, MAX, MIN, REF |
The table updates by itself whenever you change a name, value or tolerance, or stretch the part so a measured value changes — there is no need to rebuild it. To go back to numbers on a dimension, select it and click Clear names (show values).
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Open DXCAD2D OnlineNaming conventions used in practice
- Order the letters the way people read: left to right, top to bottom, or overall sizes before detail sizes.
- Avoid letters easily confused with digits, such as I and O, where you can. Automatic naming goes in sequence; rename afterwards if needed.
- Use MAX or MIN for sizes that only matter in one direction, such as an overall height that must fit a mounting space.
- Always state the unit. The generated table starts with
UNIT : mm. - If one picture serves several variants, make a table per variant (or a multi-column table with text) and note in the title block that the picture is not to scale.
For dimensioning basics, see ISO dimensioning basics.