Creating Concatenate Curves

You can create a curve from multiple touching or intersecting curves.

Before you begin: Open a 3DShape containing curves, with at least two curves intersecting each other.
See Also
Matching Surfaces
Mouse Menus
  1. Select multiple curves.
  2. From the Surfacing section of the action bar, click CurveConcatenate .

    Starting from the first selected curve, the curves to be concatenated are found at both end points with an auto-propagate functionality respecting the continuity specified in the mouse menu (Alt + right-click).

    The curves are merged if the distance between their end points is below the Topology tolerance. A new curve is created. The input curves remain unchanged.

    Note: If trimming in a certain direction is active, the distance is measured on the projection plane.
    Tip: Alternatively, you can first select a curve, click CurveConcatenate , and then click somewhere in the work area to select the next highlighted curve. You can continue the selection in this way, however, if the curve chain branches, you must explicitly select the required curve.
  3. Optional: In the case that curves are not merged, increase the Topology tolerance tolerance until the curves are merged.


  4. Change the Merge Mode to specify the behavior of spikes.
    OptionDescription
    Topological Preserve spikes as hard points without a curve approximation.
    Merge Creates an approximating smooth curve for all i.
    Merge keeping segment points Creates a smooth curve interpolating the hard points.
    Topological Merge Merge keeping segment points
  5. Define the Trim Options to merge the selected curves at intersection points in addition to curve end points.
    OptionDescription
    No Trimming Merges the curves only at their end points, one after another in the selection order.
    Trim Merges the curves at intersection points and end points.
    In View Direction Merges the curves at intersection points in the current view. Distances in view direction are ignored as long as they are smaller than Max Trim Distance.
    In X Direction Merges the curves at intersection points projected into the yz plane. Distances in x direction are ignored as long as they are smaller than Max Trim Distance.
    In Y Direction Merges the curves at intersection points projected into the xz plane. Distances in y direction are ignored as long as they are smaller than Max Trim Distance.
    In Z Direction Merges the curves at intersection points projected into the xy plane. Distances in z direction are ignored as long as they are smaller than Max Trim Distance.
    OmniPlane Merges the curves at intersection points projected into the current OmniPlane. Distances normal to the OmniPlane are ignored as long as they are smaller than Max Trim Distance.

    The pick positions determine which part of the curves connect. Consecutive curves in the selection order must touch or overlap within the Trim Tolerance (seen from the projection direction if trimming in a certain direction is active).

    No Trimming Trim




  6. Click OK.
    The input curves are set to Hide.

Be aware of the following error messages:

Not enough inputs selected Either continue selecting curves, or cancel the command and reselect in case you selected the wrong inputs.
Nothing merged

A) Input curves are not matched (distance of end points > Topology tolerance). Use OmniMatch before CurveConcatenate.

Note: Increasing the Topology tolerance works for end point matching only, not yet for trimming situations.

B) Trimming situation (end point on next curve interior), but Trim Option is set to No Trimming.

No intersection points found and nothing merged A pair of parallels situation because you sculpted curves after datum matching G1 or higher, so they are namely parallel, but have a gap in-between.
Intersection point found but nothing merged The wrong curve parts were indicated by the pick position.