We propose a method to remesh the surfaces of 3D sealed geological structural models for subsequent volumetric meshing. The input of the method is a set of triangulated surfaces that are in contact along given lines and at given points. The output is a set of surfaces meshed with triangles as equilateral as possible. The method relies on a global Centroidal Voronoi optimization to place the vertices of the final surfaces combined with combinatorial considerations to either recover or simplify the surfaces, lines and points of the input model. When the final resolution is sufficient, the input contact lines, and points are also contact lines and points of the final model. However, when dealing with models with complex contacts, resolution may be insufficient and instead of a refinement strategy that may lead to too many points, we propose to locally merge some features of the input model. This ability to simplify the input model is particularly interesting when the model is to be volumetrically meshed. The method is demonstrated on twelve structural models, including seven models built with an implicit modeling method, and one folded layer model affected by a discrete fracture network.