CGAL users discussion list

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Dear all,

 

I am new to this library and computational geometry and I am trying to use CGAL for my project. The problem is that I would like to know the shape of a 2D random point cloud’s boundary on a 2D surface. Thus I tried to get the alpha shape for this point cloud with some alpha value. Intuitively, I tried to used the optimal alpha computed by the following method.

 

Alpha_shape_2 A(points.begin(), points.end(), FT(100000), Alpha_shape_2::REGULARIZED);

A.set_alpha(*A.find_optimal_alpha(1));

 

The result can be seen in the following picture:

 

As can be seen in the picture, it contains many small holes. In order to get rid of these holes, I am thinking to increase the alpha value a little bit. However, that does not guarantee a optimal result in other cases. Therefore, I would like to ask for any suggestions and help to eliminate these small holes. Also I am curious about what the value “1” in the “A.set_alpha(*A.find_optimal_alpha(1))” means and how exactly this “find_optimal_alpha” method works. Any explanation would be appreciated. Thank you very much!

 

Best regards,

ZHAN, Xucong