Level of granularity is medium for most objects, and coarse for a few others (furniture, piping, and other objects with large number of radii). If Revit returns no faces for an object, we increase the granularity to fine and try again.
Some objects, such as structural tresses, have a mixture of faces in medium and fine.
When medium faces return vertices, the fine vertices will be ignored. Assemble collects objects and checks their type, and then extracts based on type. Assemble does not extract line types, and the webbing of structural tresses are read as lines with fine vertices.
Since Assemble does not extract lines, these objects are skipped geometrically.