# Mesh.faces and network **URL:** \ **Category:** compas\ **Created:** [May 14, 2019, 9:09am UTC](https://forum.compas-framework.org/t/mesh-faces-and-network/185 "2019-05-14T09:09:50Z")\ **Posts on this page:** 7\ **Page:** 1
**Author:** ![SalMo](https://avatars.discourse-cdn.com/v4/letter/s/a5b964/32.png) [@SalMo](https://forum.compas-framework.org/u/SalMo)\ **Post date:** [May 14, 2019, 9:09am UTC](https://forum.compas-framework.org/t/mesh-faces-and-network/185/1 "2019-05-14T09:09:50Z")
I made a mixed mesh (which is a group of several square meshes) in rhino and saved it as ._obj_ file. (see figure). I then loaded it with _mesh=Mesh.from\_obj_. Now, _mesh.face_, returns only the faces of each cell, which makes scene. So for the mesh in the figure, it mesh.face gives: _{0: [30, 8, 17, 16], 1: [3, 32, 8, 30], 2: [16, 17, 9, 12], 3: [12, 9, 0, 24], 4: [22, 34, 4, 14], 5: [29, 6, 34, 22], 6: [38, 3, 30, 36], 7: [37, 12, 24, 19], 8: [10, 37, 19, 31], 9: [6, 38, 36, 34], 10: [14, 4, 10, 25], 11: [25, 10, 31, 5], 12: [7, 18, 26, 27], 13: [35, 28, 18, 7], 14: [23, 1, 28, 35], 15: [13, 7, 27, 33], 16: [15, 35, 7, 13], 17: [20, 23, 35, 15], 18: [32, 20, 15, 17], 19: [17, 15, 13, 0], 20: [0, 13, 33, 21], 21: [19, 0, 21, 2], 22: [5, 19, 2, 11]}_ I was wondering if there is a way to instead of finding the cells, we can find real faces like: [0, 9, 17, 15, 13]. So I tried: _mesh\_2=Mesh()_ _for key, attr in mesh.vertices(True):_ _mesh\_22.add\_vertex(key, x=attr[‘x’], y=attr[‘y’], z=attr[‘z’])_ _mesh\_2.halfedge=mesh.halfedge_ _network\_find\_faces(mesh)_ This way I can get the actual faces + the boundary face, but there will be some other faces that are not correct (e.g. the ones in bold): _{0: [29, 22, 14, 25, 5, 11, 2, 21, 33, 27, 26, 18, 28, 1, 23, 20, 32, 3, 38, 6], 1: [0, 9, 17, 15, 13], 2: [9, 0, 17, 8, 32, 17, 16, 30, 8, 17], 3: [0, 13, 33, 21], **4: [17, 0, 19, 24, 0, 21, 2, 19, 0, 24, 12, 9, 0]**, 5: [1, 28, 35, 23], **6: [2, 11, 5, 19, 31, 10, 37, 19, 5, 31, 19]**, 7: [3, 32, 8, 30], 8: [38, 3, 30, 36], 9: [4, 34, 36, 30, 16, 12, 37, 10], 10: [34, 4, 14, 22], 11: [4, 10, 25, 14], 12: [5, 25, 10, 31], 13: [6, 34, 22, 29], 14: [34, 6, 38, 36], 15: [7, 27, 33, 13], 16: [27, 7, 18, 26], 17: [18, 7, 35, 28], 18: [35, 7, 13, 15], 19: [9, 12, 16, 17, 0, 19, 24, 0, 21, 2, 19, 0, 24, 12], 20: [12, 24, 19, 37], 21: [15, 17, 32, 20], 22: [35, 15, 20, 23]}_ Is there a way to cure this? ![MeshPlotter](https://us1.discourse-cdn.com/flex015/uploads/compas_framework1/original/1X/f099072b1a5f7ea8b4f0eb1ddc93b0f91f2ce499.png) ---
**Author:** ![tomvanmele](https://sea1.discourse-cdn.com/flex015/user_avatar/forum.compas-framework.org/tomvanmele/32/13_2.png) [@tomvanmele](https://forum.compas-framework.org/u/tomvanmele)\ **Post date:** [May 14, 2019, 9:29am UTC](https://forum.compas-framework.org/t/mesh-faces-and-network/185/2 "2019-05-14T09:29:01Z")
are you asking for a general solution? or something that just works in this case? ---
**Author:** ![SalMo](https://avatars.discourse-cdn.com/v4/letter/s/a5b964/32.png) [@SalMo](https://forum.compas-framework.org/u/SalMo)\ **Post date:** [May 14, 2019, 9:43am UTC](https://forum.compas-framework.org/t/mesh-faces-and-network/185/3 "2019-05-14T09:43:25Z")
Well for this case, I can remove the wrong faces, by writing a small function. But is there a general way to do this? ---
**Author:** ![tomvanmele](https://sea1.discourse-cdn.com/flex015/user_avatar/forum.compas-framework.org/tomvanmele/32/13_2.png) [@tomvanmele](https://forum.compas-framework.org/u/tomvanmele)\ **Post date:** [May 14, 2019, 10:49am UTC](https://forum.compas-framework.org/t/mesh-faces-and-network/185/4 "2019-05-14T10:49:50Z")
not really. the mesh is in fact correct because it corresponds to the input. after all, in your input face 19 did not contain vertex 9, it just contained vertices 0, 17, 15, 13. i also don’t think the solution posted above is correct at all. as you noticed, you will just get a bunch of weird faces… what you could do, is to check for the faces that share at least one vertex, which edges intersect and if both faces contain the intersection point. if this is not the case, add the vertex to the face that does not contain it. this will work in most cases i guess… ---
**Author:** ![SalMo](https://avatars.discourse-cdn.com/v4/letter/s/a5b964/32.png) [@SalMo](https://forum.compas-framework.org/u/SalMo)\ **Post date:** [May 14, 2019, 11:48am UTC](https://forum.compas-framework.org/t/mesh-faces-and-network/185/5 "2019-05-14T11:48:13Z")
Thanks for the input. Also is there another way to get vertices on the boundary. With the original mesh, the mesh.vertices\_on\_the\_boundary function will stuck. ---
**Author:** ![tomvanmele](https://sea1.discourse-cdn.com/flex015/user_avatar/forum.compas-framework.org/tomvanmele/32/13_2.png) [@tomvanmele](https://forum.compas-framework.org/u/tomvanmele)\ **Post date:** [May 15, 2019, 6:58am UTC](https://forum.compas-framework.org/t/mesh-faces-and-network/185/6 "2019-05-15T06:58:20Z")
i can see that that might be the case. in the original mesh `5, 31, 19, 24, 0, 9, 17, 8, 32` (if you move `31` and `24` slightly down and `9` and `8` slightly to the left, that fact becomes immediately clear) are also on the boundary and create loops that will confuse the algorithm. it should not get confused by something like this so i will try to release a patch as soon as possible… fwiw, the mesh can be made into the mesh that you want with the following snippet applied to faces `5, 19, 2, 11`, `19, 0, 21, 2`, `17, 15, 13, 0`, `32, 20, 15, 17` ```python fkey = mesh.halfedge[5][19] vertices = mesh.face_vertices(fkey) i = vertices.index(19) vertices.insert(31, i-1) mesh.halfedge[5][31] = fkey mesh.halfedge[31][19] = fkey del mesh halfedge[5][19] ``` which should probably also be handled by a mesh function 🙂 ---
**Author:** ![SalMo](https://avatars.discourse-cdn.com/v4/letter/s/a5b964/32.png) [@SalMo](https://forum.compas-framework.org/u/SalMo)\ **Post date:** [May 15, 2019, 7:14am UTC](https://forum.compas-framework.org/t/mesh-faces-and-network/185/7 "2019-05-15T07:14:37Z")
Great. Thanks for the help. Looking forward to it.