While this has been discussed in some variations before, I fear it may wrongly be considered obsolete due to the new build tools, so I bring it up again.
For a start, having the slice-tool affect user-built structures and trees in addition to the soil would be more consistent.
What works currently
- While designing multi-floor buildings, the new build tools allow hiding upper floors.
- When mining, and using the slice view, buildings whose floor is far above slicing level are hidden.
What doesn’t work
- The “hide floors” tool affects only what was placed by the “Rooms” tool, which however is too limited for more complex layouts (rectangles only!), where manually placed blocks and walls may be used heavily (e.g. in order to have the floor of an upper story fit with the color of the walls; see e.g. attachment  for an example why this is needed).
- There is currently no way to hide floors of a finished building while outside of the builder tool. Rearranging furniture, or replacing furniture by higher-quality versions, is therefore not really possible on lower floors.
- Buildings are only hidden, if their floor level is at least 2 slices above the current slice setting (see Slice view: Bad compatibility with buildings?).
- If a building is high, it will still be in the way of mining, if the ground level of the building is below the current slicing level. See attachment .
- Likewise, trees are not affected by the slice-tool, making the use of trees as city-decoration hard (see , ).
 High buildings in the way of mining dispite slice view.