How to get concave hull？

[jcwwc]

Please use the following template to help us solving your issue.

Issue Details

I want to know how to get the concave hull boundary of point cloud.
I tried alpha Shape, but I still got convex hull.

Source Code

This is the official instance code：
CGAL-5.1.3\examples\Alpha_shapes_2

Environment

• Operating system (Windows/Mac/Linux, 32/64 bits): windows + vs2017
• Compiler:
• Release or debug mode: release & debug
• Specific flags used (if any):
• CGAL version: 5.13
• Boost version: 1.64
• Other libraries versions if used (Eigen, TBB, etc.): pcl qt

[sloriot]

Did you see that page?
https://doc.cgal.org/latest/Manual/tuto_reconstruction.html