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CreateBsplineSurface Method (IModeler)

Creates a b-spline surface.

.NET Syntax

Visual Basic (Declaration) 
Function CreateBsplineSurface( _
   ByVal Props As System.Object, _
   ByVal UKnots As System.Object, _
   ByVal VKnots As System.Object, _
   ByVal CtrlPtCoords As System.Object _
) As System.Object
Visual Basic (Usage) 
Dim instance As IModeler
Dim Props As System.Object
Dim UKnots As System.Object
Dim VKnots As System.Object
Dim CtrlPtCoords As System.Object
Dim value As System.Object
value = instance.CreateBsplineSurface(Props, UKnots, VKnots, CtrlPtCoords)
System.object CreateBsplineSurface( 
   System.object Props,
   System.object UKnots,
   System.object VKnots,
   System.object CtrlPtCoords
System.Object^ CreateBsplineSurface( 
&   System.Object^ Props,
&   System.Object^ UKnots,
&   System.Object^ VKnots,
&   System.Object^ CtrlPtCoords


Array containing 8 integers packed as 4 double elements (see Remarks)
Array of numUKnots (see Remarks)
Array of numVKnots (see Remarks)
Array of numCtrlPtCoord (see Remarks)

Return Value

B-spline surface


The Props array contains the following elements. These are integers packed into a double array in the Dispatch version.

  • Uorder, Vorder

  • numV_CtrlPoints, numU_CtrlPoints

  • Uperiodicity, Vperiodicity

  • DimensionControlPoints, UNUSED ( set =0 )


Number of elements in this array...

Given by...


numUKnots = numU_CtrlPoints + Uorder


numVKnots = numV_CtrlPoints + Vorder


numCtrlPtCoord =( NumV_CtrlPoints * NumU_CtrlPoints * DimensionControlPoints )

NOTE: The order of the UV control points are reversed if you used ISurface::GetBSurfParams3 or ISurface::IGetBSurfParams to get the data. You do not need to reverse the UV control points; instead, you can switch the UV knots and related parameters.

For periodics, the first knot must have multiplicity = 1 and all excess multiplicity must be imposed on the last knot. Therefore, a valid periodic knot vector would be { 0, 1, 2, 3, 3, 3 } for a cubic curve. The control point on the seam of the closed curve cannot be replicated at both ends; it should occur only at the beginning.

To convert from a clamped periodic curve (numKnots = numCtrlPts + Order, ctrlPts replicated, knot multiplicity = order at each end) to a SOLIDWORKS periodic curve, remove all but one of the knots at the beginning of the vector and remove one at the end. Also remove the last control point to avoid the point replication.


See Also

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