Hello everybody, First, thanks a lot for your neat work on openmesh! I am creating meshes for 3D modelling as a part of my masters thesis and I am glad to use a well written library. I am able to build many things and play with it thanks to openmesh, however I encounter some troubles from time to time. I asked some communities (stackoverflow for instance) but the subject does not seem to be hot right now, and experts are hard to find, so I am asking you. I use openmesh with Python 3.6. Openmesh was installed with a 'pip install openmesh' : *1/ First*, I wanted to add custom propetries to vertices of the mesh, it does work but does not write in the file, or it is not read when the file is re-opened, here is my code : import openmesh as OM import numpy as np mesh = OM.TriMesh() #Add some vertices vh0 = mesh.add_vertex(np.array([0,0,0])); vh1 = mesh.add_vertex(np.array([1,0,0])); vh2 = mesh.add_vertex(np.array([1,1,0])); vh3 = mesh.add_vertex(np.array([0,1,0])); #Create some data data = np.arange(mesh.n_vertices) #Add custom property for vh in mesh.vertices(): mesh.set_vertex_property('prop1', vh, data[vh.idx()]) #Check properties have been added correctly print(mesh.vertex_property('prop1')) #prints data matrix OM.write_mesh('mesh.om',mesh) #Re-load mesh in another instance : mesh1 = OM.TriMesh() mesh1 = OM.read_trimesh('mesh.om') #Check property is still there print(mesh1.vertex_property('prop1')) #Prints a matrix of 'None'... So, I cannot save then read a custom property. (So far, I save custom properties into a csv file, which is okay but not convienient.) *2/ Another issue* I encounter is when I want to save a mesh into a vtk file. The writter writes nothing . Here is my code : import openmesh as OM mesh = OM.TriMesh() #Add some vertices vh0 = mesh.add_vertex([0,0,0]) vh1 = mesh.add_vertex([0,1,1]) vh2 = mesh.add_vertex([1,0,1]) vh3 = mesh.add_vertex([1,1,0]) #Add some faces (we are building a tetrahedron here) mesh.add_face(vh0,vh1,vh2) mesh.add_face(vh0,vh2,vh3) mesh.add_face(vh0,vh3,vh1) mesh.add_face(vh1,vh3,vh2) OM.write_mesh('TEST_MESH.vtk',mesh) Nothing is written. (When I put .ply or .om ... instead of .vtk, it works just fine) According to the documentation, it should work, so I don't know what I am doing wrong. If you have any tips or advices, it would be very appreciated, Thank you for your time, thank you for your help, Charles Duvert.