Creating Silhouettes

This task shows you how to create silhouettes.
Silhouette is a 3D wire. The silhouette command computes reflect lines, extracts edges that define the contour and removes non-visible areas of the contour. For example, in case of a car, it computes the vision cones of objects that are inside a car from the view point of the passenger.
Open the Silhouette1.CATPart document.
Display the Project-Combine sub-toolbar by clicking and holding the arrow from the Projection icon.

  1. Click Silhouette in the Wireframe toolbar (Project-Combine sub-toolbar).

    The Silhouette Definition dialog box appears.

  2. Select the Type of silhouette to be created:

    • Cylindrical: corresponds to the silhouettes with an infinite light source.
    • Conical: corresponds to the silhouettes with a finite point light source.

      By default, the Cylindrical option is selected.

  3. In the Support box, select one or multiple surfaces.

  4. Select an axis for the Direction box (for cylindrical type) or a point for the Origin box (for conical type).
    Cylindrical silhouette

  5. In case of a cylindrical silhouette, in the Projection plane box, select a planar element.
    The filtered silhouettes are projected on this plane.
     
    Conical silhouette

  6. In case of a cylindrical silhouette, select Curve or Surface to create the result.
    • Curve: allows you to create one dimensional silhouette.
    • Surface: allows you to create two dimensional silhouette.

    By default, the Curve option is selected.

  7. Select the Result filters to obtain the desired result:
    • External: allows you to keep the external silhouette edges.
    • Internal: allows you to keep the internal silhouette edges.
    • Inside: allows you to keep the silhouette edges other than internal and external ones.
      This option is available only when one element is selected as support element.
    If no specific result filter is selected, all silhouettes are kept.

  8. Click OK to create the element.
    The silhouette (identified as Silhouette.xxx) is added to the specification tree.
     
    Cylindrical  silhouette
    Conical silhouette

    3D silhouettes are not necessarily closed.