The user desired the ability to dimension along a line/edge that was not co-linear with the base coordinate system.
This can be simply done by using the Dimension Axis option and the Distance Between tool.
1. When in the Dimension Between tool select Use Dimension Axis.
2. Click on the set Dimension Axis button.
3. Then, select the line or edge that you want to use as the axis to dimension relative to.
4. Place the dimension as you normally would.