Click Calculations ( ) in the toolbar.

The Calculations dialog opens with three tabs, CoG, Distance, and Sphere.  For more information on the other tabs, see Calculating the Center of Gravity and Calculating the Center of a Sphere.

In the Distance tab of the Calculations dialog, under Action select Select an Edge.

In the workspace, click an edge to analyze.

If the selected edge is periodic, distance is computed using the start and midpoint of the edge.  Otherwise, distance is computed using the start and end of the edge. The results show the $\mathrm{\Delta }$X, $\mathrm{\Delta }$Y, and $\mathrm{\Delta }$Z and the total distance.

(Optional) If desired, click Create Coordinate at Midpoint.

The coordinate is placed. In the Tree View, coordinates are indicated by this icon:  

Note: The orientation of the coordinate is determined using the normal of the point you clicked on.  Because of this, to control the orientation, orient the view before starting this process, so that the surface normal you want as the coordinate Z points directly at the camera.

In the Distance tab of the Calculations dialog, under Action select Select 2 Coordinates.

Select the first coordinate. You can select it in the Tree View or Workspace.  You can place a coordinate if you have not already, and that coordinate will then be used.

Select the second coordinate.

The distance between the selected coordinates is computed. The results show the $\mathrm{\Delta }$X, $\mathrm{\Delta }$Y, and $\mathrm{\Delta }$Z and the total distance.

(Optional) If desired, click Create Coordinate at Midpoint.

The coordinate is placed. In the Tree View, coordinates are indicated by this icon:  

Note: The orientation of the coordinate is taken from the orientation of the first coordinate.

After the midpoint is created, you can continue the process. Point B will be updated to the now selected new midpoint, and if you press the button again, you create another new coordinate.  This time it will be $\frac{1}{4}$ of the distance along the original AB line segment.