AutoCAD Geometry 中BoundedPlane 是平行四边形，不是三角形

第一次使用这个类，

起初以为这个BoundedPlane 是三角形，

没想到在求取交点时，

有交点位于三角形之外，

在QQ群193522571中请教，

群友45168391告诉我BoundedPlane是平行四边形，

不是三角形，

并且告诉我需要对对加过进行判断，

或者简单的求两次，

用不同的BoundedPlane的来求，

都能得到交点，

交点必然在三角形之中。

Point3d p1 = new Point3d();
Point3d p2 = new Point3d(3, 0, 0);
Point3d p3 = new Point3d(1, 3, 0);
Point3d p4 = new Point3d(3, 2, 0);
Point3d p5 = new Point3d(3, 2, 1);

Point3d p6 = new Point3d(3, 4, 0);
Point3d p7 = new Point3d(3, 4, 1);

BoundedPlane bp1 = new BoundedPlane(p1, p2, p3);
BoundedPlane bp2 = new BoundedPlane(p2, p3, p1);
BoundedPlane bp3 = new BoundedPlane(p3, p1, p2);

var l1 = new LineSegment3d(p4, p5);
var l2 = new LineSegment3d(p6, p7);

var pts11 = l1.IntersectWith(bp1);
var pts12 = l1.IntersectWith(bp2);
var pts13 = l1.IntersectWith(bp3);

var pts21 = l2.IntersectWith(bp1);
var pts22 = l2.IntersectWith(bp2);
var pts23 = l2.IntersectWith(bp3);

if (pts11 != null)
{
    Autodesk.AutoCAD.ApplicationServices.Application.ShowAlertDialog("bp11交点个数为：" + pts11.Length);
}
if (pts12 != null)
{
    Autodesk.AutoCAD.ApplicationServices.Application.ShowAlertDialog("bp12交点个数为：" + pts12.Length);
}
if (pts13 != null)
{
    Autodesk.AutoCAD.ApplicationServices.Application.ShowAlertDialog("bp13交点个数为：" + pts13.Length);
}
if (pts21 != null)
{
    Autodesk.AutoCAD.ApplicationServices.Application.ShowAlertDialog("bp21交点个数为：" + pts21.Length);
}
if (pts22 != null)
{
    Autodesk.AutoCAD.ApplicationServices.Application.ShowAlertDialog("bp22交点个数为：" + pts22.Length);
}
if (pts23 != null)
{
    Autodesk.AutoCAD.ApplicationServices.Application.ShowAlertDialog("bp23交点个数为：" + pts23.Length);
}