Creating a Curves Network

You can create a network of constrained curves as a datum.

This task shows you how to:

See Also
About Curves Networks

Select Curves and the Support Mesh

You can clean the curves used to create the network.

See Recommended Workflow for more information.

  1. From the Wireframe section of the action bar, click Curves Network .
  2. In the Preparation tab, select the curves to clean:
    1. Select a clean contour, a curves network, or a join of curves.
      Their curves are added to the list.
    2. Select the mesh that supports the curves network.

    Notes:
    • It is better to select a support mesh, although it is not compulsory.
    • Median lines of fillets created in Curve Network Preparation are automatically discarded from the selection.
    • Fictive edges can be selected with or without associated border lines. The associated guiding curve is discarded, as are the median lines of fillets.
    • Fictive edges are system frozen, not adjustable.
    • Frozen curves are displayed in the Freeze tab.

  3. To remove a curve from the list, do one of the following:
    1. Pick the curve again in the work area.
    2. Pick the curve again in the tree.
    3. Right-click the curve and select Remove.
  4. Optional: Enter the Max distance value.

    Below this value, two curves are considered as intersecting each other.

  5. Optional: Check the Filtering check box and enter a value to filter small sliced curves.
  6. Click Apply.
    Wires are computed and displayed:
    • If errors prevent the creation of the network (for example overlapping curves), a message is displayed, the faulty node, curves, or wire are highlighted in red.
    • If the creation is successful, the network is displayed in green, with a circle on each node.

Check Frozen Curves

You can control frozen curves from the Freeze tab.

See Frozen Curves for more information.

  1. Go to the Freeze tab.
    • The list of frozen curves is displayed for information (No interaction: You cannot add curves to the selection and specify them as frozen).
    • They are displayed in the 3D area.
    • Standard curves: Standard display.
    • Fictive edges: Thick dark blue.
    • User frozen curves: Dotted dark blue.
    • Face borders: Thick green.
  2. Click a curve in the 3D area to change its status.

    Possible changes are:

    • Standard curve > User frozen > Standard curve.
    • Fictive edge > User frozen > Fictive edge.

    The display is updated.

Display the Quality of the Network

You can use the display options in Analyze to verify the quality of the network.

  1. Select the Sharp/Smooth edges check box to display edges according to their continuity.

    • By default, the check box is selected.
    • Sharp edges (with G0 continuity) are displayed in black.
    • Smooth edges (with G1 continuity) are displayed in gray.

  2. Select the Distances at nodes check box to display the minimum 3D distance between two curves at their pseudo-intersection.
    They are displayed in yellow except for the greatest minimum distance found that is displayed in black.
  3. Click this black callout to update Max distance in the Preparation tab with a value that takes all curves pseudo-intersection into account.
  4. Select the Spikes check box to display deviation curvatures spikes:
    1. Click to display the deviation spikes between the network curves and the input curves.
    2. Click to display the deviation spikes between the network curves and the support mesh.
    3. Click to display the curvature spikes on the network curves.
      Spikes within the tolerance are displayed in green, spikes exceeding the tolerance are displayed in red.
  5. Use the Spikes scale slider to define the size of the spikes and the Spikes density slider to define their density.
  6. Select the Max deviation check box and:
    1. Click to display the maximum deviation between the network curves and the input curves.
    2. Click to display the maximum deviation spikes between the network curves and the support mesh.

    • You can combine Spikes and Max deviation.
    • When Max deviation alone is selected, the greatest corresponding spike is displayed.
    • Max deviation is not relevant for the curvature.

    Note: Although this is possible, do not combine Max deviation with Distances at nodes as it would be difficult to read the combined information.

Constrain the Curves

You can constraint the curves used to create the network.

  1. Select the Constraints tab to define constraints.

    Default constraints lets you revert to the default constraints.

    The existing constraints are highlighted:
    • As a green dot for continuity constraints on nodes.
    • As a blue line for tangency constraints.
    • As a red curve for frozen curves.
    Important:
    • The constraints are applied globally on the whole network.
    • Continuity constraints on nodes are implicit and cannot be removed.
  2. Set the Node tolerance.

    • It defines the maximum distance between edges extremities to consider these edges connected on a node.
    • It cannot be smaller than Max distance.
    • It is visualized as a green sphere whose radius is equal to the node tolerance. The size of this sphere is updated when you modify the Node tolerance value. Move the sphere with the cursor.

  3. Select the Automatic tangency check box to activate tangency constraints.
    1. Optional: Edit the value of the tangency angle.
    2. Click Apply after each modification.
  4. Select the Projection on support check box to compute the network from the projections of the curves on the mesh.

    This is only possible if you have selected a support mesh.

    This parameter can be edited. It is applied to all curves.

    Recommendation: Do not select this check box when the selection includes fictive edges since it could lead to unexpected results.

    The projected curves are smoothed with the Smoothing tolerance.
  5. Select the Global deformation check box to apply a global deformation constraint, or clear it to apply a local deformation constraint (available for all deformable edges).

    This constraint is applied during the geometric adaptation step.

    • Global deformation is selected, edges deformations are done along the entire length of the edges:

    • Global deformation is not selected. The deformation is local:

  6. Select the Merge Consecutive Curves check box.

    It simplifies the topology by merging curves. See Merge Consecutive Curves (Datum Only) for more information.

Delete Wire

Deleting wire and Delete wire are available from the Preparation tab, after an Apply.

  • A wire is computed on each loop of curves, plus a large one on the loop formed by the external curves because the network is considered as closed by default.
  • If the network does not form a closed volume, you usually do not need this large wire (it would create an additional surface as you create surfaces from the curves network).
  • In the same way, you can remove wires corresponding to holes in your part.

  1. Click Deleting wire to activate the wire selection.
    The large wire is highlighted and Delete wire becomes available.
  2. Click Delete wire to remove this wire.
    • To create a surface on a network of curves with a hole in it, that is, without filling one or several wires:
      • Click Deleting wire to activate the wire selection.
      • Pick two edges of the wire.
      • Click Delete wire.
    • If you do not remove the large wire, an information message is displayed as you click OK. Click Yes or No according to your needs.

A CurvesNetwork element is created.