February 2021 - OpenMesh - lists.rwth-aachen.de

OpenMesh with OpenMP
by LuWang (Jack) 14 Dec '23

14 Dec '23

Hello Madam or Sir, I am the user of OpenMesh, and I want ask some questions about the parallel code with OpenMesh, exactly, the parallel code is based on OpenMP on the VS2013. The first question: When I use the OpenMP on the VS2013 to speed up the program which write with OpenMesh, for example, I add the code: #pragma omp parallel for num_threads(7) , just like the following: and the errors follow, and I do not know why. and the second question: Could the code with iterator of OpenMesh be paralleled by OpenMP just like " for (TriMesh::FaceIter f_it = mesh.faces_begin(); f_it != mesh.faces_end(); f_it++) " in the above picture? or How can I parallel the code with iterator of OpenMesh? Thank you for your time! And I am looking forward to your reply. Sincerely LuWang

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inf values in texture coordinates when writing obj file
by Vladimir Privalov 05 Mar '21

05 Mar '21

Hi. I have problem with UV texture coordinates of vertices stored in obj file after writing mesh to obj file. I set UV coordinates for a vertex using method set_texcoord2D(). When explore the resultant obj file I see some inf values in 'vt' lines of the file. The UV values I set from code have no inf values. What could be the problem? Thanks, Vladimir Privalov

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Feature Request: Make export precision a mesh trait
by Alexander Schier 12 Feb '21

12 Feb '21

Hello, I have a feature request. The write_mesh method has a precision parameter, that is by default 6, which controls how many decimal places of vertex coordinates are written when exporting the mesh. When using double precision coordinates, 6 decimal places is little. In fact, I had several times algorithms that did not converge when float was used in the export function (I think it was fixed in 8.1) and now require to set the precision to a larger value when exporting the mesh. It would be good to add the precision to the mesh traits classes and increase it in the DefaultTraitsDouble class. One note on the new DefaultTraitsDouble class, but probably hard to change now that people are using it: Why does it use Vec4f Color, making it incompatible with the DefaultTraits class that uses Vec4uc Color? It would be really nice to have a DefaultTraitsDouble class included that is identical to the DefaultTraits class except for the precision of the floating-point vectors. with kind regards, Alexander Schier

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Issue with saving texture coordinates in obj file
by Vladimir Privalov 09 Feb '21

09 Feb '21

Hi. I have a problem with saving texture coordinates in obj file. I am using Python version of OpenMesh for manipulating with texture coordinates in 3D mesh stored in obj file. I save the result mesh using method write_mesh. When I open the resultant obj file there is no texture coordinates information, only list of vertices and faces. The same happens if I read the mesh from obj file. What could be the problem? Thanks. Kind regards, Vladimir Privalov

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IO::write - concurrent writing
by btyukodi＠brandeis.edu 02 Feb '21

02 Feb '21

Dear OpenMesh Devs, It appears now to me that there is a problem when using IO::write concurrently, from different threads even though these write operations should be independent as they operate on separate meshes and separate streams. When I move the writing operations outside my parallel section, it works fine. When inside the parallel section, I'm getting the double free error quite randomly so I assume that whenever writing is attempted at the same time from multiple threads, it fails. Any idea about why this is happening or any fix would be greatly appreciated. Thank you, Botond

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