HI,
Could you please give a suggestion for the task that: - I have a list of line segments. I need to find out faces (cells) generated by intersecting the segments. Could you suggest me which functions should I use to implement the cell decomposition by intersecting lines and get information of the cells (faces, vertices, edges) . - Is it possible to achieve adjacent relation between cells (for instance, cells i is in adjacent (neighbour) with ceill j,k, m etc)? Could you please suggest which package and function should I use to complete this task? I am new to CGAL. Thank you so much. I appreciate any comment & suggestion. Best regards, Anne -- Sent from: http://cgal-discuss.949826.n4.nabble.com/ -- You are currently subscribed to cgal-discuss. To unsubscribe or access the archives, go to https://sympa.inria.fr/sympa/info/cgal-discuss |
IIUC your problem you can use the arrangement package:
https://doc.cgal.org/latest/Arrangement_on_surface_2/ by considering the unbounded face. Here is a small example on how to iterator over halfedges of the holes of the unbounded face. https://gist.github.com/sloriot/5a2f69951c8902948392c9368cc23ab4 Sebastien. On 06/11/2018 04:15 PM, Anne wrote: > HI, > > Could you please give a suggestion for the task that: > - I have a list of line segments. I need to find out faces (cells) generated > by intersecting the segments. Could you suggest me which functions should I > use to implement the cell decomposition by intersecting lines and get > information of the cells (faces, vertices, edges) . > > - Is it possible to achieve adjacent relation between cells (for instance, > cells i is in adjacent (neighbour) with ceill j,k, m etc)? > > Could you please suggest which package and function should I use to complete > this task? I am new to CGAL. Thank you so much. I appreciate any comment & > suggestion. > > Best regards, > Anne > > > > -- > Sent from: http://cgal-discuss.949826.n4.nabble.com/ > -- You are currently subscribed to cgal-discuss. To unsubscribe or access the archives, go to https://sympa.inria.fr/sympa/info/cgal-discuss |
I got it. I give it a try. Thank you so much.
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This post was updated on .
In reply to this post by Sebastien Loriot (GeometryFactory)
Is there anyway to extract the vertices (in order clockwise or counter
clockwise) for each of the holes (cells)? I have tried the code with five segments (as given in the code sample) and it just produce only one hole (As I imagine, it should produce ~ 7 holes in total) (please refer to the Figure 1). For example, I insert an image here for better explanation about my problem, could you suggest the way to get the vertices & edges for each bounded faces (e.g., F1, F2,F3,F4) which formed by intersecting the line Segments (1, 2, ...,6) (Please refer to the Figure 2) Thank you. Figure 1: Figure 2: <http://cgal-discuss.949826.n4.nabble.com/file/t375966/cell_decomposition.jpg> -- Sent from: http://cgal-discuss.949826.n4.nabble.com/ -- You are currently subscribed to cgal-discuss. To unsubscribe or access the archives, go to https://sympa.inria.fr/sympa/info/cgal-discuss |
I understood that you were only interested in the unbounded face.
But if you iterator over all the faces of the arrangement you can also get bounded faces. Something like: Face_const_iterator fit; std::cout << arr.number_of_faces() << " faces:" << std::endl; for (fit = arr.faces_begin(); fit != arr.faces_end(); ++fit) { } Sebastien. On 06/13/2018 05:06 AM, Anne wrote: > Is there anyway to extract the vertices (in order clockwise or counter > clockwise) for each of the holes (cells)? I have tried the code with five > segments (as given in the code sample) and it just produce only one hole (As > I imagine, it should produce ~ 7 holes in total). > > For example, I insert an image here for better explanation about my problem, > could you suggest the way to get the vertices & edges for each bounded faces > (e.g., F1, F2,F3,F4) which formed by intersecting the line Segments (1, 2, > ...,6) > Thank you. > <http://cgal-discuss.949826.n4.nabble.com/file/t375966/cell_decomposition.jpg> > > > > -- > Sent from: http://cgal-discuss.949826.n4.nabble.com/ > -- You are currently subscribed to cgal-discuss. To unsubscribe or access the archives, go to https://sympa.inria.fr/sympa/info/cgal-discuss |
This post was updated on .
Thanks. any function in CGAL can directly extract the adjacent relation
between the bounded faces? I appreciate your help. -- Sent from: http://cgal-discuss.949826.n4.nabble.com/ -- You are currently subscribed to cgal-discuss. To unsubscribe or access the archives, go to https://sympa.inria.fr/sympa/info/cgal-discuss |
It is based on a halfedge data structure. So the boundary of each face
is a sequence of halfedges and adjacent faces share opposite halfedges. Everything is written in the manual. Sebastien. On 06/15/2018 10:01 AM, Anne wrote: > Thanks. any function in CGAL can help to extract the adjacent relation > between the bounded faces? I appreciate your help. > > > > -- > Sent from: http://cgal-discuss.949826.n4.nabble.com/ > -- You are currently subscribed to cgal-discuss. To unsubscribe or access the archives, go to https://sympa.inria.fr/sympa/info/cgal-discuss |
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