About Creating Curved Objects (VBA/ActiveX)

You can create a variety of curved objects with AutoCAD, including spline curves, circles, arcs, and ellipses.

All curves are created on the XY plane of the current WCS.

To create a curve, use one of the following methods:

AddArc

Creates an arc given the center, radius, start and end angles.

AddCircle

Creates a circle given the center point and radius.

AddEllipse

Creates an ellipse given the center point, a point on the major axis, and the radius ratio.

AddSpline

Creates a quadratic or cubic NURBS (nonuniform rational B-spline) curve.

Create a Spline object

This example creates a spline in model space using three points (0, 0, 0), (5, 5, 0), and (10, 0, 0). The spline has start and end tangents of (0.5, 0.5, 0.0).

Sub Ch4_CreateSpline()
  ' This example creates a spline object in model space.
  ' Declare the variables needed
  Dim splineObj As AcadSpline
  Dim startTan(0 To 2) As Double
  Dim endTan(0 To 2) As Double
  Dim fitPoints(0 To 8) As Double

  ' Define the variables
  startTan(0) = 0.5: startTan(1) = 0.5: startTan(2) = 0
  endTan(0) = 0.5: endTan(1) = 0.5: endTan(2) = 0
  fitPoints(0) = 1: fitPoints(1) = 1: fitPoints(2) = 0
  fitPoints(3) = 5: fitPoints(4) = 5: fitPoints(5) = 0
  fitPoints(6) = 10: fitPoints(7) = 0: fitPoints(8) = 0

  ' Create the spline
  Set splineObj = ThisDrawing.ModelSpace.AddSpline(fitPoints, startTan, endTan)
  ZoomAll
End Sub