About Creating References for 3D Design
You can use centerlines, center points, and coordinate systems as references to map 2D geometry and define the placement of a layout in the 3D environment. The entities are automatically tagged as public and are shared with a 3D design.
Use these 2D geometric entities to mark various types of references in a 3D design:
• Centerline—Marks the center of cylindrical geometry and rotational symmetry.
• Center point—Marks the center of cylindrical geometry and rotational symmetry.
• Coordinate system—Marks the relative location and orientation of entities.