Joins two or more curve object together to form one or more curves or polycurves.
Rhino.JoinCurves (arrObjects [, blnDelete [, dblTolerance]])
| arrObjects | Required. Array. An array of strings identifying the curve objects to join. | 
| blnDelete | Optional. Boolean. Delete input objects after joining. The default is not to delete objects (False). | 
| dblTolerance | Optional. Number. The join tolerance. Of omitted, 2.1 * the document's absolute tolerance is used. | 
| Array | An array of strings identifying the newly created curve objects if successful. | 
| Null | If not successful, or on error. | 
Const rhObjectCurve = 4
Dim arrObjects
arrObjects = Rhino.GetObjects("Select curves to join", rhObjectCurve)
If UBound(arrObjects) > 0 Then
Rhino.JoinCurves arrObjects
End If