Simcenter 3D Solutions Creating an Intersection Point of Two Curves using NX Open

NXOpen.Point	NXOpen.PointCollection.CreatePoint	(	NXOpen.IBaseCurve	curve1
			NXOpen.IBaseCurve	curve2
			NXOpen.Point	helpPt1
			NXOpen.Point	helpPt2
			NXOpen.SmartObject.UpdateOption	updateOption
		)

Case 1

Point3d pt3d_1 = new Point3d(0.0, 0.0, 0.0);
Point3d pt3d_2 = new Point3d(3.0, 3.0, 3.0);
Point3d pt3d_3 = new Point3d(2.0, 0.0, 0.0);
Point3d pt3d_4 = new Point3d(2.0, 3.0, 3.0);

Point point_1 = workPart.Points.CreatePoint(pt3d_1);
Point point_2 = workPart.Points.CreatePoint(pt3d_2);
Point point_3 = workPart.Points.CreatePoint(pt3d_3);
Point point_4 = workPart.Points.CreatePoint(pt3d_4);

Line line_12 = workPart.Curves.CreateLine(point_1, point_2);
Line line_34 = workPart.Curves.CreateLine(point_3, point_4);

Point answerPt = workPart.Points.CreatePoint(line_12, line_34, nullPt, nullPt, SmartObject.UpdateOption.WithinModeling);

Produces the expected point at coordinates [ 2.0, 2.0, 2.0 ] because the line segments intersect in 3D space

Case 2

Point3d pt3d_5 = new Point3d(0.0, 0.0, 0.0);
Point3d pt3d_6 = new Point3d(1.0, 1.0, 1.0);
Point3d pt3d_7 = new Point3d(2.0, 0.0, 0.0);
Point3d pt3d_8 = new Point3d(2.0, 1.0, 1.0);

Point point_5 = workPart.Points.CreatePoint(pt3d_5);
Point point_6 = workPart.Points.CreatePoint(pt3d_6);
Point point_7 = workPart.Points.CreatePoint(pt3d_7);
Point point_8 = workPart.Points.CreatePoint(pt3d_8);

Line line_56 = workPart.Curves.CreateLine(point_5, point_6);
Line line_78 = workPart.Curves.CreateLine(point_7, point_8);

Point answerPt = workPart.Points.CreatePoint(line_56, line_78, nullPt, nullPt, SmartObject.UpdateOption.WithinModeling);

Throws an exception.  Even though the projected lines of these segments intersect, the actual segments do not intersect.

The workaround is shown in the next case.

Case 3

Point3d pt3d_5 = new Point3d(0.0, 0.0, 0.0);
Point3d pt3d_6 = new Point3d(1.0, 1.0, 1.0);
Point3d pt3d_7 = new Point3d(2.0, 0.0, 0.0);
Point3d pt3d_8 = new Point3d(2.0, 1.0, 1.0);

Point point_5 = workPart.Points.CreatePoint(pt3d_5);
Point point_6 = workPart.Points.CreatePoint(pt3d_6);
Point point_7 = workPart.Points.CreatePoint(pt3d_7);
Point point_8 = workPart.Points.CreatePoint(pt3d_8);

InfiniteLine line_9 = workPart.Curves.CreateInfiniteLine(pt3d_5, pt3d_6);
InfiniteLine line_10 = workPart.Curves.CreateInfiniteLine(pt3d_7, pt3d_8);

Point answerPt = workPart.Points.CreatePoint(line_9, line_10, nullPt, nullPt, SmartObject.UpdateOption.WithinModeling);

Produces the expected point at coordinates [ 2.0, 2.0, 2.0 ], though the segments do not intersect, using an infinite lines using the segment values produces the desired value.