Use-Edges

  Before you begin with use-edges: You should be familiar with important concepts.
Project 3D elements onto the view plane: create geometry in the current design view by projecting a 3D element onto the view plane.
Intersect 3D elements with the view plane: create geometry in the current design view by intersecting a 3D element with the view plane.
Project 3D silhouette edges: create geometry in the current design view by projecting the silhouette edge of a 3D element onto the view plane.
  Create associative use-edges: create associative use edges.