About Use-Edges

This sub-topic explains what use-edges are.

Use-edges are key in a concurrent engineering process, helping you with your design by letting you re-use existing elements from a 3D shape coming from another designer for example. In other words, use-edges help you create geometry from existing 3D shapes as well as from other layouts.

The Sketcherapp provides the following use-edge functionality:

• Projecting 3D Elements onto the Sketch Plane: lets you create geometry by projecting a 3D element onto the sketch plane.
• Intersecting 3D Elements with the Sketch Plane: lets you create geometry by intersecting a 3D element with the sketch plane.
• Projecting 3D Silhouette Edges: lets you create geometry by projecting the silhouette edge of a 3D element onto the sketch plane.
• Projecting 3D Canonical Silhouette Edges: lets you create geometry by projecting the cylindrical edges of a 3D cylindrical element onto the sketch plane.
• Offsetting 3D Elements: lets you create offset use-edges that will be associative to 3D elements (surfaces or edges)

You can create multi-domain use edges (silhouette, intersections, projections) with multiple domains in geometrical result.

Multi-domain use-edges are composed of multiple marks. Therefore, any modification done on the geometrical input specification is reflected on mark geometries. As a result, during update, marks can be created, deleted or modified.

During update, use-edges are modified according to their geometrical input specifications and use-edge marks are also modified to match those changes.

Consider the following case of multi-domain use-edge displaying multiple marks:

The following table describes the geometrical modifications done on this use-edge and their effect on mark geometries:

Geometrical Modification	Use-edge after Update	Marks after Update	Result
Domain associated to mark is removed.			Constraints relying on the mark are destroyed and the associated mark is removed.
Domain is merged into another domain.			Marks corresponding to merged domains are not destroyed, but both are associated to the whole merged domain.
Domain is modified and a new domain is created.			When domain is modified, each mark associated to previous domain is transformed to match the new geometrical result of this domain. When a new domain is created, a new mark is created, and is associated to this domain.

This topic provides information about associative use-edges.

• Associative use-edge marks are used as other 2D curves to create dimensions, constraints.
• Use-edges are visualized in yellow with thickness as defined in Sketcher settings for color of protected elements.
• A mark is always a curve, or a point. This curve can be the result of an edge, a vertex or the concurrence of several edges coming from the projection of face. The last kind of mark is also called composite mark which symbolized by an letter box icon in the tree.
• Use-edge is always a fixed geometry. It cannot be moved, copied, or pasted.
• When trimming or breaking a use-edge mark, an arc of use-edge is created.
• When the input geometry of a use-edge or the plane support of sketch changes, the use-edge mark are up-to-dated automatically. In the case of manual update, the update icon appears in the tree on the node of the pertinent sketch.
• When a use-edge is deactivated, then it is not updated even if the input geometry or the view plane changes.

  Activating or deactivating a use-edge mark will activate or deactivate all marks for that use-edge.

• When deleting a use-edge mark, the whole use-edge is deleted.
• Use-edges which have geometry imported from other 3D shapes as an external reference or a datum geometry, will not be deleted when the use-edges are deleted.

  You must delete these imports specifically if you do not need them anymore.

• You can isolate a use-edge using the context menu available on each mark.

  When isolating a use-edge mark, this use-edge and its marks are deleted and replaced by identical standard 2D geometries, with no link to the input geometrical element.

  Dimensions and annotations created on this use-edge marks are not automatically rerouted to new isolated geometries.

  The Isolate command is also available in the Use-edges tab of the Sketch Analysis dialog box, using the Sketch Analysis command from the Tools section of the action bar.

• In the Search options list, select Find to search for the associative use-edges of the following types:
  • Projection
  • Intersection
  • Silhouette
  • Mark
• Associative use-edge inputs are listed in the tree under the Use-edges node.
• You can delete use-edge inputs in the tree. When you delete a use-edge input, all use-edges impacted by this input will be marked as up-to-date.
• Use-edges can be analyzed in the Sketch Analysis command, in the Use-edges tab of Sketch Analysis dialog box.

This topic provides information about input geometries for associative use-edges.

Geometrical inputs of a use-edge can be located in the same 3D shape representation than the 2D layout representation, or in an external representation. The following types of geometries can be provided as inputs:

Use-edge functionality	2D Geometries	2D Use-edges	Vertices	Edges	Faces	Volumes	Bodies
Projection	Yes	No	Yes	Yes	Yes	Yes	No
Intersection	Yes	No	Yes	Yes	Yes	Yes	Yes
Silhouette	No	No	No	No	Yes	Yes	Yes
Offset	Yes	No	No	Yes	Yes	Yes	No

When creating a use-edge from a geometrical input external to the 3D shape, a geometrical import will be created in the current 3D shape. Whether this geometrical is linked to the original geometry depends on the option Keep link with selected object, in Me > Preferences > Common Preferences > Object Properties > 3D Shape > Infrastructure > External References tab.