Dimensions in sketches
The Sketch Dimension tool lets you add dimensions to sketch and construction geometry in an active sketch in Fusion.

Sketch Dimension
The Sketch Dimension tool creates dimensions to define and constrain geometry in the active sketch. Use dimensions to control the size and position of sketch geometry.
You select the sketch curves to dimension, then click to place the dimension in the canvas.
Driving dimensions
A Driving dimension is a dimension that is used to explicitly define measurement values of geometry.
Driving dimensions are the default type of dimension created by the Sketch Dimension tool, unless the dimension will over-constrain the sketch.
Driven dimensions
A Driven dimension is a dimension whose value is flexible, and is determined by geometry or other dimensions, parameters, or expressions.
Driven dimensions:
- Are automatically added when the dimension you are adding will over-constrain the sketch.
- Display their calculated value in parentheses.
- Update automatically as the geometry, dimensions, parameters, or expressions that drive them change.
- Display as read-only values in the Parameters dialog, in parentheses and greyed out.
You can reference a Driven dimension within the same sketch, across different sketches, and in modeling features.