public void RotateAboutLine(clsLine3d l1, double theta)
{
clsPoint3d p1 = default(clsPoint3d);
clsPoint3d p2 = default(clsPoint3d);
clsPoint3d p2a = default(clsPoint3d);
clsPoint3d p2b = default(clsPoint3d);
clsPoint3d p3 = default(clsPoint3d);
clsLine3d l2 = default(clsLine3d);
if (l1.IsOnLine(this))
{
return;
}
//Setup a coordinate system with X running along l1 and the origin at l1.p2
l2 = new clsLine3d(l1.P2.Copy(), Copy());
p1 = new clsPoint3d(l1.DX(), l1.DY(), l1.DZ());
p1.Length = 1;
p2 = new clsPoint3d(l2.DX(), l2.DY(), l2.DZ());
p2a = new clsPoint3d(l2.DX(), l2.DY(), l2.DZ());
p2.Length = 1;
p3 = p1.Cross(p2);
p3.Length = 1;
p2 = p1.Cross(p3);
p2.Length = 1;
if (p2.Dot(p2a) < 0)
{
p2.Scale(-1);
}
p2b = new clsPoint3d(p1.Dot(p2a), p2.Dot(p2a), p3.Dot(p2a));
p2b.RotateAboutX(theta);
myX = l1.X2 + p2b.x * p1.x + p2b.y * p2.x + p2b.z * p3.x;
myY = l1.Y2 + p2b.x * p1.y + p2b.y * p2.y + p2b.z * p3.y;
myZ = l1.Z2 + p2b.x * p1.z + p2b.y * p2.z + p2b.z * p3.z;
}