Matching Surfaces

You can extend one surface to another surface or a curve by specifying the type of match between the two elements.

When you select a frozen surface (a surface with a history) or a non-Nurbs surface as input, a dialog box is issued warning you that an automatic conversion will be performed before the matching operation:

  • When an exact conversion is possible, a new Nurbs surface will replace the input one in order to perform the match. This new surface will be added in the tree.
  • When there is a deviation or no exact conversion exists, the Converter Wizard dialog box appears allowing you to define the approximation according to a tolerance using parameters such as U, V orders, patch numbers, and deviation tolerance.

Before you begin: Open an existing 3D shape.
See Also
Match Surface Dialog Box
  1. Optional: In the App Options panel, click Keep Original .
  2. From the Edition section of the action bar, click Match Surface .
  3. Click More>> in the Match Surface dialog box.
  4. Select an edge of the first surface.

    You can select edges either from outside the surface (i.e. the pointer points towards the surface) or from within the surface (i.e. the pointer is over the surface when selecting the edge).

  5. Move the cursor onto the second surface.
    • indicates that the element has one support.
    • indicates that the element has more than one support. Right-click the tag to display the available supports and select the one you want to use.
  6. Click the surface when the boundary you want is highlighted.
    • The match is automatically applied.
    • The first surface is recomputed so as to be connected to the second surface.
    • The continuity labels are displayed close to the matched surface (in the App Options panel, click Continuity ). When a continuity type leads to some inconsistencies, a message is displayed on the surface, so that you can modify the continuity type.
    • Handles are displayed on the connection (in the App Options panel, click Contact Points ).


  7. Right-click a continuity label to change the continuity type.
    • Point: The surfaces share each point of their common boundary, i.e. there is no gap between the surfaces.
    • Tangent: The surfaces share a common tangent plane (i.e. normal) at each point of their connection.
    • Curvature: The surfaces share a common curvature and tangent plane at each point of their connection.
    • Proportional: Similarly to the Tangent option, surfaces share a common tangent plane (i.e. normal) at each point of their connection, but the longitudinal variation from one point to the other is smoother, as the system automatically re-distributes the control point location on the matched surface. This mode is automatically set for both limits of the matched surface.
    • Free: No constraint is imposed on the curve control points.
  8. Use the handles to interactively define the match limits by simply sliding them along the target curve.

    wTo edit the contact points, right-click the point and select Edit.

  9. Set the continuity types to Point on the initial surface and Tangent on the target surface.


  10. In the App Options panel, click Tensions .
    The tension values are displayed on the element along with a green segment representing the direction and limits of the match surface tangent at its middle-points.

  11. Modify the tension values by doing one of the following:
    • Slide the tension value along the direction.
    • Right-click the tension value, select Edit tension, and enter a new value within the 0 to 1 range.
    • Right-click the tension value and select Invert direction to invert its direction.
  12. Clear Tensions .
  13. Modify the surface order.


  14. Select Quick connect checker and orders.
    The quick connect checker displays the angle between the two surfaces.

  15. Select Control Points and click OK to recompute the match surface.
    The Control Points dialog box appears.

    The control points and mesh lines are displayed on the initial surface. When a modification is not consistent with constraints previously set, as the choice of continuity for example, a message is displayed on the geometry. You then have the choice not to perform the modification, or to modify the constraint in order to edit freely the control points.



  16. Click OK.


Available capabilities from the App Options panel, and/or specified in Me > Preferences > App Preferences > 3D Modeling > Styling > FreeStyle Shape Design, General tab, are: