CGAL users discussion list

[Leon Nan <>]

Hi all,

I am using CGAL::linear_least_squares_fitting_3() to fit planes from point 
set. It works pretty well for data set with more than 3 points. But I was 
surprised that this function behaved when fitting a plane form 3 points. The 
function returned 0.495031, which meant the variance orthogonally to the 
fitting plane was quite big. Acutally 1.0 is expected because 3 points are 
exactlly in the same plane. Can someone explain?

Here is the code I call the fitting function:
                Plane3f plane;
                double q = CGAL::linear_least_squares_fitting_3(
                        pts.begin(), 
                        pts.end(), 
                        plane,
                        CGAL::Dimension_tag<0>()
                        );


And the input(only 3 points):
        ==================================
                86.1817 3075.31 1031.53
                164.575 3075.31 913.936
                754.546 0 28.9401
        ==================================

--
Leon
http://web.siat.ac.cn/~liangliang/