Sketcher > Dimensioning Sketcher Geometry > Working with Dimension Tools > About the Dimension Tools
  
About the Dimension Tools
Use these dimension tools to dimension Sketcher entities:
Normal—Creates a linear, radial, diameter, angular, conic, or ordinate dimension. Works in Continue mode.
Perimeter—Dimensions the total length of a chain or a loop of entities.
Baseline—Creates linear dimension entities based on the position of the first selection. All subsequent selections are measured relative to the first selection.
Reference—Creates a symbolic dimension for the entity.
 
* Reference dimensions can be toggled to Normal dimensions.