Is your feature request related to a problem? Please describe.
It's sometimes difficult to build when there's lots of hologram blocks next to each other. Normally need to go layer-by-layer, but this wastes efficiency.

Describe the solution you'd like
An option to only display placeable blocks -- that is, schematic blocks that are next to real world blocks.

Describe alternatives you've considered
Well, the existing approach is somewhat solved with transparency. Can more clearly discern what is going on, but can still sometimes be overwhelming.