In the Clipper transformer, try to remove "_geometry" from the "group by" option.

"Group by" is used to process subsets. Like clipper with ID=1 vs clippee with ID=1 and clipper with ID=2 vs clippee with ID=2.

Leaving "Group by" option empty unfortunately does not help. The point cloud is still entirely "Outside" only difference is "_fme_no_clipper" is set to no.

I thought that "Group by" determined which groups to form after clipping rather than which clipper to use on which clippee? From Clipper documentation about "Group by" parameter: "This option allows you to select attributes that define which groups to form"

The problem lies in your buildings. Inspecting them they are multi-surface 3D objects of the fme_type: surface and fme_geometry: aggregate. You want them to be of the fme_type: area and fme_geometry: polygon (not sure if you need both).

One way of achieving this is to run them through a 2DForcer (a SurfaceFootprintReplacer works too) before sending them to the Clipper. I tried that, and then it works.

Another way is to first Deaggreate the building objects and then use a GeometryCoercer set to fme_polygons.

There are usually multiple ways to solve something with FME, and I'm pretty convinced that there might be an even smarter way. 🙂

This does appear work after all, though I get a different result from the one that was gotten in 2020.0 version. Thank you!

There appeared to have also been another issue with my CityGML dataset. The X and Y coordinates were either flipped or not flipped depending on whether I opened it directly in Inspector or if I opened it in inspector through workbench. I seem to have fixed that now.