You can add fixed, floating, or free straights and curves to a layout profile.
Use constraint-based commands on the Profile Layout Tools toolbar to refine the layout profile design to meet your project objectives.
Note: When drawing or editing constraint-based profile entities, ensure that the Profile Layout Tools toolbar is set to 
Entity Based mode.
Entity Based mode. The three element type describes the way an element is defined and edited:
- Fixed elements are defined by specifying parameters, such as pass-through points, straight slope, and curve radius. The elements are fixed in position and must be edited directly. Except for its length, the geometry of a fixed element is not dependent on adjacent elements. If an adjacent element is edited, the geometry of the fixed element is not affected.
- Floating elements are defined by specifying parameters and an element to attach to. Floating elements are always straight to the element they are attached to, and are dependent on the other element to define their geometry.
- Free elements are defined by attachment to two elements, before and after. The free element always remains straight to the two adjacent elements, and its geometry is defined by these adjacent elements.