Cap is a modeling tool which creates a smooth freeform end ("cap") on a part. The shape of a cap is determined by properties about its vertex ("cap point") and connecting edges with the part. It is possible to specify a smooth transition from the cap to specified existing faces.
The following factors determine the finished shape of a cap:
• The edges of the part from which the cap is built. You can also specify which sides of the part are to be deleted.
• The cap point. This is the peak of the cap. It can be raised to create a convex cap or it can be lowered to create a concave cap.
• The tangent angle and tangent weight between cap and part faces. (You can also specify no smooth connection.) The relative weight indicates to what degree the cap faces will follow the tangent of the connecting faces.
• The tangent plane at the cap point. This plane controls the regularity and symmetry of the cap.
• The tangent weight at the cap point. The relative weight indicates to what degree the cap surface will remain close to the tangent plane. This determines how rounded the cap will be, from pointed to flat.
In the following figure, (1) is the part to be capped. (2) shows a strongly convex cap; its cap point is in a fairly high position. (3) shows a concave cap; the cap point is in a fairly low position. (4) shows a slightly convex cap with both tangency weight and cap weight set to unity. (5) uses the same cap point as (4); however, the tangent weight is large, while the cap weight is set to unity. (6) also uses the same cap point as (4); however, the cap weight is large, while the tangent weight is set to unity. (7) shows a cap angle of -30 degrees with unity tangent weight and unity cap weight. (8) uses a non-vertical cap normal.
Like other Surfacing tools, Cap either constructs a new face part, or adds a face to an already existing part.
The Preview option allows you to make a visual check of the new geometry before accepting it, and Check Part tells Creo Elements/Direct Modeling to look for errors in the geometry. While using Preview extensively to make fine adjustments to a cap, keep Check Part turned off to save processing time. Turn it back on when the cap is finished.
To create a surface with Cap,
1. Activate the Surfacing module.
a. Click File > Modules. The Modules dialog box opens.
b. On the Modules pane, click Surfacing under Licensed.
2. Click Surfacing and then, in the Advanced Surfacing group, click Cap. The Cap and Select dialog boxes open.
3. If necessary, specify the part.
4. Click Edges. The Select menu appears with the Start option already active.
5. Click the edges defining the base of the cap, or specify them in another way.
6. Click End in Select.
7. To position the cap point, move the
Point 3D CoPilot in the Viewport to the desired length and angle, then click.
8. Click Cap Vector to specify the cap normal and weight. Cap normal is the normal of the tangent plane at the cap point. Cap weight is the relative weight of the tangent plane at the cap point. The initial direction for the Cap Vector is taken from the W axis of the Point CoPilot's handle.
9. Click Side to determine which connecting faces of the part are to be deleted.
10. Specify the tangency conditions you want to apply to the cap surface:
◦ If you want the cap surface to meet existing faces tangentially, click Tangents and select To Faces.
◦ If you want to apply user-defined tangency conditions to the cap surface, select User Def. The All option is on.
▪ To define tangents for all vertices belonging to the highlighted set of edges:
1. Click Direction and use the options in the
Direction 3D tool.
2. Click Weight and enter a weight (between 0.2 and 5 - the greater the number, the stronger the pull of the tangent).
▪ To modify all vertex tangents of the set:
1. Click All and specify a new direction and weight for all vertex tangents.
▪ To modify single vertex tangents:
1. Click Single.
2. Click a vertex with a tangent.
3. Click Direction and use the options in the Direction 3D tool to specify a new direction for the tangent at this vertex.
4. Click Weight and enter a weight for the tangent.
5. Click another vertex. The vertex tangent gets the same tangent conditions as the previous vertex tangent. To give new tangent conditions proceed as above.
▪ Otherwise, click None.
11. If you specified To Faces, you can enter the tangent angle and tangent weight. The default values are 0 degrees and 1.
12. Click Angle to specify the angle at which the cap is connected to its neighboring faces. The default is 0 degrees (implying a smooth connection).
13. Click Weight to specify the smoothness of the cap with respect to its neighboring faces. The default is 1 (implying a smooth connection).
14. If you want a smooth connection to the adjacent face, rather than the side face, click Adjacent.
15. Click AutoWeight if you want to optimize both tangent weight and cap weight for maximum cap smoothness. When you select AutoWeight, the tangent plane Weight button is grayed out.
Cap. The Cap and Select dialog boxes open.
to complete the operation.