How do I edit a dimension after I place it, and will it update when I resize the part? (12.5 editable dimensions)

What changed in 12.5

Dimensions used to be close to static annotations. In 12.5 they became editable objects: you can drag their handles, and the measured value follows the geometry when the dimension is scaled along with its part.

Edit an existing dimension

With the Dimensions form open (either view):

1. Open the Dimensions tool.
2. Hold Shift and click the dimension you want to change.
3. Adjust font, text height, decimal places, Offset or custom text on the form.

Directly in the 3D view with drag handles:

• White handles change the overall height and width of the dimension object and the position of the text. On an arc dimension they can also change the radius.
• Black handles change the leg length and the text height.

Keep dimensions live when resizing

The documentation states that the value updates dynamically as the dimension object is scaled, and that this also works when the dimension is grouped with other vectors and the group is scaled. So the reliable workflow is:

1. Select the part and its dimensions together (or group them).
2. Scale the selection.
3. The dimension text now reads the new size.

If you scale only the part and leave the dimension unselected, the dimension is not part of the scale and will not follow.

Custom text gotcha

Use Custom Text replaces the measured value with your own words. Custom text is stored per dimension, so you can switch back to calculated text without losing it, but while it is on, the label will not change when the part is scaled. If a dimension refuses to update, check that box first.

Other details worth knowing

• Angle dimensions have their own Decimal Places setting, separate from the other types, and allow up to six decimal places.
• Arc dimensions only work on true arc spans. Circles that were converted to straight segments, or Bezier spans, cannot be dimensioned.
• Dimension text snaps to the middle of the dimension line. Hold Shift while dragging to place it freely.
• By default dimensions go onto their own mid-gray Dimensions layer, which makes them easy to hide before toolpathing.

Pro tips

• Build 12.509 and 12.510 fixed crashes tied to the decimal places control, so update if the tool crashes on you.
• Keep the Dimensions layer out of your toolpath selections. See the entry on using layers effectively.