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does anyone know of GPL (preffrably MIT) code for computing a concave hull of a 3D point set. I know there are functions in CGAL for doing this but I cannot use CGAL atm. If possible a MIT implementation would be nice or even GPL for a proof of concept before I spend the time implementing it myself. Any explanation of some concave / alpha shape algorithm would be good too to better understand how to go about implementing this. I'm struggling to find c++ implementations of alpha_shapes_3/concave hull. I'm looking for other implementations other than CGAL essentially or an explanation of alpha shapes algorithm.

Thankyou.

[EDIT:] Put another way... is there anything other than CGAL which does 3D alpha shapes, MIT would be nice to save me doing it, but a dedicated open source project would also suffice which is isolated and not part of a framework. Failing that any information of algorithms for doing this 3D would also be appreciated.

lfgtm
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  • Library recommendations are off-topic. – Ron Oct 08 '18 at 11:12
  • If you don't say why you cannot use cgal, we don't know if the same reasons may apply to other libraries... – Marc Glisse Oct 08 '18 at 11:23
  • @MarcGlisse, currently can't deploy with LGPL or afford lic for CGAL. I cannot find any other implementation for alpha_shapes_3 (3D Concave hull) implementation or details of an algorithm for this. Lots for 2D, but not 3D :( – lfgtm Oct 08 '18 at 11:32
  • @Ron. doesn't have to be recommended ;)... atm I'm happy with just an "existence of" or explanation! – lfgtm Oct 08 '18 at 11:33
  • You say you cannot use (L)GPL and then ask for GPL libraries... Look for libraries that build a Delaunay triangulation, that's most of the work of building an alpha-shape. – Marc Glisse Oct 08 '18 at 13:14
  • @MarcGlisse, thanks for your replies, yeah sorry I meant LGPL in the qu. I'm not looking to deploy with (L)GPL, just to looking understand some algorithms without digging down/reverse engineering CGAL. I have delaunay tessellation routines, but the step to get the alpha shape is big extra step. Delaunay produces meshes more akin to convex. I'm looking for concave. Before spending time implementing one myself I was wondering if there are any others so I can do proof of concept/better understanding before commiting. There are lots for 2D but not 3D. Seems CGAL is the only one. – lfgtm Oct 08 '18 at 14:17

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