Failed Frontal 3D mesh; Edge multiple times in surface
I'm attempting to create a volume mesh with multiple internal nested volumes. I perform a segmentation and volume meshing in Amira, and export that mesh as Nastran to read the volume mesh into GMSH. I have a separate stl surface that wraps around the entire imported volume, and I'm creating a 3D mesh in the void between the exterior surface and interior volume meshes. When attempting a frontal 3D mesh, I get the following error:
Error : ERROR: Edge 4 - 9 multiple times in surface mesh
Meshing with the Deluanay algorithm, however, works. I assume that this error is due to duplicate nodes, but I've tried cleaning up the merged volume mesh using removeDuplicateNodes() but that doesn't seem to work.
Is this error due to duplicate nodes and any suggestions for fixing the issue? I'd at least like to understand why the Frontal algorithm is failing. The volume mesh from Amira is too large to drop here, but I've included the python script so you can see my steps and a zip file of the .msh. Thanks!