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IGetBSurfParams Method (ISurface)

Gets the b-spline surface parameters for the surface.

.NET Syntax

Visual Basic (Declaration) 
Function IGetBSurfParams() As System.Double
Visual Basic (Usage) 
Dim instance As ISurface
Dim value As System.Double
 
value = instance.IGetBSurfParams()
C# 
System.double IGetBSurfParams()
C++/CLI 
System.double IGetBSurfParams(); 

Return Value

  • in-process, unmanaged C++: Pointer to an array of doubles (see Remarks
  • VBA, VB.NET, C#, and C++/CLI: Not supported

    See In-process Methods for details about this type of method.

  • Remarks

    For COM applications, the following values must be set up in a previous call to ISurface::IGetBSurfParamsSize3:

    • vP0 [0] & vP0 [2] are the lower bounds of the U & V surface parameters, respectively.
    • vP0 [1] & vP0 [3] are the upper bounds of the U & V surface parameters, respectively.

    If you want to use the Bsurface in combination with its trim curves, you should use the IFace2::GetTrimCurves2 method to extract the trim curves and the Bsurface. The IFace2::GetTrimCurves method provides better alignment of the trim curves with the Bsurface because they are both generated at the same time.

    Evaluation is as follows:

    Number of returned double elements is (4 + NumUKnots + NumVKnots + NumControlPointDoubles), where NumUKnots = (NumColumnsControlPoints + Uorder) and NumVKnots = (NumRowsControlPoints + Vorder).

    The returned data are arranged in the following order:

    • Uorder, Vorder - These are two ints packed into a double

    • Uorder - Order of surface in U direction.

    • Vorder - Order of surface in V direction.

    • NumColumnsControlPoints, NumRowsControlPoints - These are two ints packed into a double

    • NumColumnsControlPoints - Number of columns for the control points.

    • NumRowsControlPoints - Number of rows for the control points.

    • Uperiodicity, Vperiodicity - These are two ints packed into a double. Because you may be generating a Bsurface with this function, the U,V periodicity values may be opposite from the original surface. See ISurface::Parameterization or ISurface::IParameterization.

    • Uperiodicity - TRUE if surface is periodic in U direction.

    • Uperiodicity - TRUE if surface is periodic in V direction.

    • DimensionControlPoints, dummy - These are two ints packed into a double

    • DimensionControlPoints - Dimension for control points.

    • DimensionControlPoints = 3 for non-rational surfaces and control point coordinates are output as [x0,y0,z0,x1,y1,z1,.........].

    • DimensionControlPoints = 4 for rational surfaces and control point coordinates and the weight are output as [x0,y0,z0,w0,x1,y1,z1,w1,........].

    • dummy - a system used filler.

    • UKnots - Knot vector in the u direction

    There will be (NumColumnsControlPoints + Uorder) knot values. If the surface is periodic in the U direction, then data will be converted and returned in a non-periodic form with additional knots added to the surface ends.

    • VKnots - Knot vector in the v direction.

    There will be (NumRowsControlPoints + Vorder) knot values. If the surface is periodic in the V direction, then data will be converted and returned in a non-periodic form with additional knots added to the surface ends.

    • ControlPoints - This is a list of control points output in (NumColumnsControlPoints*NumRowsControlPoints) vectors of dimension DimensionControlPoints. The vectors are output row by row. The U direction of surface is in the row direction. The V direction of surface is in the column direction.

    • For non-rational surfaces, control point coordinates are output as [x0,y0,z0,x1,y1,z1,.........].

    • For rational surfaces, control point coordinates and the weight are output as [x0,y0,z0,w0,x1,y1,z1,w1,........].

     

    See Also



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