Dynamo Meshes - unstable?

Hello, I started a new topic for my old question (Revit surfaces to mesh per Revit element - double loop), as I have the feeling that my problem is getting bigger and can be related to instability of Dynamo/Revit when it comes down to meshes. For the purpose of my graph, I refer to the old post.

Problem1: I cannot use the batch mesh.BooleanUnion method for combining multiple meshes coming from surfaces from one Revit object. Some meshes will combine and others not; this seems to be random.

Problem2: When I export the resulting meshes with the mesh.ExportMeshes to OBJ, I get some strange behaviour. I let Dynamo run manually and I export one mesh at a time. When I do a first export, all is good. When I do a second export (other mesh and other file name to write to in the same folder) however (and if I let my first exported OBJ file in the same location), Dynamo overwrites the first OBJ file with the new export (the original file name is ‘intact’ but the content is now the same as the new OBJ) and also writes a new OBJ (with the new name).

Some pointers:

  • Revit 2018 (and 2017 tested)
  • Dynamo v (core+Revit)
  • Packages:
  • Clockwork for Dynamo 1.x (v1.0.3)
  • MeshToolkit (v 1.3.1)
  • Rhythm (v 2017.6.21)
  • SteamNodes (v 1.2.3)