Joining Curves or Surfaces

You can assemble adjacent curves or surfaces to one element.

Note: You can only assemble elements of the same type.

This task shows you how to:

Before you begin: Create a 3D shape containing at least two surfaces or two curves.

Create Joined Elements

  1. From the Assemble section of the action bar, click Join .
  2. Select the surfaces or curves to be joined in the work area or in the tree.
    The selected elements are added to the Elements to Join list.

    You can activate Add Mode , Remove Mode , or Both Mode options.

    • To add a line at the end of the rows in the table, click .
    • To remove all lines in the table, click .

  3. Alternatively
    1. Select the elements to join.
    2. Click Join in the context toolbar.



    1. Double-click Join.x feature in the tree to open the Join dialog box.
  4. You can edit the Elements to Join list as follows:
    • Click a selected element in the work area to cancel the selection and remove it from the list.
    • Right-click the elements in the list and select Clear Selection to cancel the selection of all elements.
    • Select one element in the list, right-click, and select Replace Selection. Then select another element in the work area to replace the element in the list.
    • Double-click the required mode to activate it permanently.
  5. Right-click the elements from the list and select Check Selection.
    This lets you verify whether an element to be joined presents any intersection (that is, topological errors) with other elements before creating the joined surface.

    The Checker dialog box is displayed, containing the list of domains (that is, sets of connected cells) belonging to the selected elements from the Elements To Join list.

  6. Click Preview.

    Self-intersections detected are displayed on the geometry in the work area.



  7. Click Cancel to return to the Join box.
  8. Right-click the elements and choose the propagation options to allow the selection of elements with the same dimension.
    • Distance Propagation: the tolerance corresponds to the Merging distance value.
    • Angular Propagation: the tolerance corresponds to the Angular Threshold value, if defined. Otherwise, it corresponds to the G1 tolerance value as defined in the part.

    For more information about Distance Propagation and Angular Propagation, see Using the Check Options.

    Each new element found by propagation of the selected elements is highlighted and added to the Elements To Join list.

    Important:
    • The initial element to propagate cannot be a sub-element.
    • Forks stop the propagation.
    • Intersections are not detected.
  9. Click Preview in the Join dialog box.
    The joined element is previewed and its orientation displayed. Click the arrow to invert it if required.

    The join is oriented according to the first element in the list. If you change this element, the join's orientation is automatically set to match the orientation of the new topmost element in the list.

Using the Check Options

  1. Select the Tangency check box to check whether the transitions between the elements are tangent continuous.

    If they are not, an error message is issued when you click Preview advising you to modify the selected inputs. The elements in error are highlighted in the 3D geometry once you have clicked OK in the Update Error dialog box:



    Important: This option works for an angular resolution of 0.5 degrees.
  2. Select the Check connectivity check box to check whether the elements to be joined are connected.

    If they are not, an error message is issued indicating the number of connected domains in the resulting join and elements in error are highlighted in the 3D geometry.

    Tip: When clicking Preview, the free boundaries are highlighted, and help you detect where the joined element is not connected.
  3. Select the Check manifold check box to find out whether the resulting join is manifold.
  4. Expand Advanced.
  5. Select the Simplify the result check box to allow the system to automatically reduce the number of elements (faces or edges) in the resulting join whenever possible.
  6. Select the Ignore erroneous elements check box to let the system ignore surfaces and edges that would not allow the join to be created.
  7. You can also set the tolerance at which two elements are considered as being only one using the Merging distance.
    Important: By default, the value is set to 0.001 mm and corresponds to the value defined in Preferences. For more information, see General Settings.
    Warning: Do not join two geometric elements with a merging distance exactly equal to the distance between these elements.
  8. Select Heal merged cells for topologically healing the joined elements.

    This option uses the tolerance value specified in the Merging Distance box.

  9. Expand Tolerant Modeling.
  10. In the Merging Distance box, specify the required value.
  11. Select the Angular Threshold check box and specify the angle value below which the elements are to be joined.
    Tip: If the angle value on the edge between two elements is greater than the Angle Threshold value, the elements are not joined. This is particularly useful to avoid joining overlapping elements.
    Important: This option only applies to edges merged during the join computation. To compute the angle, the middle of each merged edge is taken into account.

Removing Sub-Elements

  1. Click the Sub-Elements To Remove box to display the list of sub-elements in the join.
    These sub-elements are elements making up the elements selected to create the join, such as separate faces of a surface, for example for, that are to be removed from the join being created.

    You can edit the sub-elements list as described above (in step 3) for the list of elements to be joined.

  2. Select the Create join with sub-elements check box to create a second join of all sub-elements displayed in the list that are not to be joined in the first join.
    Important:
    • This option is active only when creating the first join, not when editing it.
    • It is not available when the joined surface belongs to an ordered geometrical set or a part body created in an environment.
    • A message is displayed to inform you of the creation of a second join.
  3. Click OK to create the joined surface or curve.
    The surface or curve (identified as Join.xxx) is added to the tree.

Tips: Select the Surface Boundaries check box in Me > Preferences > Main Preferences > Display, Visualization tab, Colors section, to check whether small gaps exist between elements.

Create a Federation

You can hybrid combine several elements to a federation. The combined elements are treated as a single element. You cannot select the elements of a federation individually in the work area.

This is especially useful when modifying linked geometry to avoid re-specifying all input elements.

Before you begin: Open a 3DShape with several surfaces and a sketch.

  1. Add all surfaces to the Elements to join list.
  2. Expand Advanced.
  3. From the Propagation Mode list, select Tangent continuity.

    The system automatically selects the elements making up the federation, taking this propagation mode into account.

    You can optionally select on of the followingP:

    • No federation: no element can be selected
    • All: adds all elements of the join feature to the federation. Selection is disabled.
    • Point continuity Tangent continuity: adds all elements with the defined transition.
    • Tangent continuity: all elements tangent to the selected element are part of the federation. Only the top faces of the joined surface are detected, not the lateral faces.
      Important: To federate a surface and its boundaries in tangency, you need to select the face as well as the edges: both face and edges are federated.
    • No propagation: adds only the elements explicitly selected to the federation.

    You can edit the Elements to join list as described in Joining Curves or Surfaces.

  4. Select the surfaces to be added, to the federation.


  5. Click OK to create the join.

Use the Federation Capability

  1. Move to the Part Design app, select the sketch and click Pad in the Model section of the action bar to create an Up to surface pad, using the joined surface as the limiting surface.


  2. Select the upper front edge of the pad.


  3. Click Edge Fillet in the Refine section of the action bar and create a 2mm fillet.


  4. Double-click the sketch from the tree, click the constraint on the sketch to change it to 10mm in the box.
    The sketch is now lying over one face only.
    before modification after modification
  5. Click to exit the Sketcher app.
    The pad can automatically be recomputed, because the faces are combined to a federation and treated as a single element.

  6. Double-click the join, select No propagation mode in the Join dialog box and click OK.
  7. Click OK in the Join dialog box.
    A message is displayed indicating the edge no longer recognized on the pad.
  8. Click OK.
    The Update Diagnosis dialog box is displayed, allowing you to re-enter the specifications the edge and its fillet. You then need to edit the edge and redo the fillet to obtain the previous pad up to the joined surface.
  9. Select the line indicating the lost edge and click Edit.
  10. Click OK in the Edit dialog box showing the lost edge in the Selected element box.
    The fillet is recomputed based on the correct edge.

Remove Lost Edges automatically

If elements of a join feature have been replaced, you can remove them from the Elements to join list in one step.

Before you begin: Open a part with a join feature, for example consisting of two faces of a rectangular volume created from a sketch.

  1. In the tree, double-click the sketch, delete the geometry, create a circle instead, and exit the Sketcher app.
    The Pad is recomputed and the Update Diagnosis dialog box opens.

    Edges that are no longer recognized on the pad appear in the work area.



  2. Select the first line and click Edit.

    The Feature Definition Error panel appears. Do one of the following:

    • Click Yes to remove all deleted sub-elements from the Elements To Join list and select the sub-elements again.
    • Click No to preserve them and be able to edit them manually.