public void RotateAboutY(double a)
{
clsPoint3d p1 = default(clsPoint3d);
p1 = new clsPoint3d(-x, z, 0);
p1.Rotate(a);
x = -p1.x;
z = p1.y;
}
public void RotateAboutZ(double a)
{
clsPoint3d p1 = default(clsPoint3d);
p1 = new clsPoint3d(x, y, 0);
p1.Rotate(a);
x = p1.x;
y = p1.y;
}
public void RotateAboutX(double a)
{
clsPoint3d p1 = default(clsPoint3d);
p1 = new clsPoint3d(y, z, 0);
p1.Rotate(a);
y = p1.x;
z = p1.y;
}