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Placement Table[]

Blocks destroyed on extention[n 1] Blocks destroyed on retraction Blocks that stop extention[n 2] Blocks not destroyed
Upwards-facing pistons
Sideways-facing pistons
Sideways-facing pistons

N/A

  1. If the block can be placed on an extended piston, it will also be broken on retraction.
  2. If the block is placed on the extended piston, it will be destroyed on retraction.

- pressure plates require the block below to have a rim (e.g. hopper) or center point on top (e.g. glass pane)
- rails require the block below to have a rim
- banners and cakes require the supporting block to be a solid material (materials should probably be documented somewhere)
- bells and levers require the supporting face to be "full"
- carpet just needs to be above anything but air
- lanterns need a center point on top (if place on top) or below (if placed below) -- for example a lantern can hang below a down-pointing hopper but can't be placed on top
- redstone dust requires a full face below, but is also hardcoded to allow hoppers

The "rim" and "center point on top" are apparently well-defined in-game predicates; for example, the center point is a 2x2 center square on the hitbox (not visual box) assuming the surface is a 16x16 square grid. Quoting tryashtar on the "rim", "It's a predicate that is created specifically by removing the entire center section from a full cube, leaving only the, well, rim".

In references to other placement quirks (by tryashtar):

Sea pickles just check if the below block has a non-empty upward face
Not a block but item frames are really interesting, they can be placed anywhere that doesn't intersect with their hitbox (and support block material must be solid (or a repeater/comparator))

By the same person, on leaves' exceptional behavior:

Leaves are considered to have faces that are "full" but not "sturdy"

Rigid blocks (blocks that require a rim):

Center blocks (blocks that require a center):

  1. Pressure plates can also be placed on blocks with only a center
  2. Pressure plates can also be placed on blocks with only a rim

Blocks that require a sturdy face:

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