A given element may have only one of the Horizontal, Vertical, or Slope constraints assigned to it. If you attempt to assign a Slope constraint to an element that is already constrained Horizontal or Vertical, the Slope constraint will replace the existing constraint.

Parametric Design defines the slope of a linear element as the angle which is swept by rotating the vector (1,0) to the intrinsic vector of the element. This intrinsic vector is the line that runs from the first to the second endpoint of the element. The intrinsic vector of a construction line depends on how it was created. This method is used so that rotations greater than 90° can be specified.

As a result of the method used to measure slope, it is not possible to visually determine the slope of a linear element from the graphics display. For example, a vertical line may have a slope of 90° or 270°, depending on whether it was constructed from "top to bottom" or "bottom to top." You can, however, read the current slope from the prompt line in step 3 of the assignment procedure above.