Selecting underground features sometimes does not work

EDIT: it turned out to be a bug (however weird) on our side. Underground selection in Cesium is all right.


Hi, I’m a developer of https://luucy.ch – a platform for urban planning, mainly targeted at Switzerland.

We noticed a really weird behavior of underground picking. In most of configurations it does not work at all but there is a singular case where the functionality is determined by a rectangular geographical boundary. So far I was not able to make any progress on the bug, so I’ll be glad for any clues on what may be the reason and what may be wrong.

To see the corner case for yourself:

  1. Open https://beta.luucy.ch/lu-2893, dismiss the pop-up window and enable 50% terrain transparency in the top-right panel (see attached image)
    1b) Wait until terrain loads and move the cursor on an underground part of a house. There’s no visual response.
  2. Move your view to e.g. Zürich (or use this location link)
    2b) Move the cursor on an underground part and the house will be highlighted in blue. That is the behavior we’d like to have.

Do you have any guess what might be going on?

EDIT: the failing rectangle is actually stored somewhere in our data. The bug may be related to Cesium.flyToBoundingArea(polygon). I’ll investigate further details.

The rest of this post is not relevant to the issue.


The correct behavior appears to be limited outside of an axis-aligned rectangle. The coordinates of the corner seem to be rather random, not anything we would set in our Cesium configuration or in the displayed data.

So far I didn’t bother to test if underground selection works anywhere outside of Switzerland.