A finite horizontal plane that acts as a reference for level-hosted forms and points. 3D levels display in the conceptual design environment as the cursor moves over them in the drawing area. These can be set as work planes.
A planar surface on which to draw lines for creating a form. 3D levels and 3D reference planes can be set as work planes. These automatically display in the conceptual design environment as the cursor moves over them in the drawing area.
A single curve, or collection of end-connected curves which are used singly or in combination to construct form element geometry, using the supported geometry construction techniques: extrude, loft, sweep, revolve, and surface.