Jump Cancel

Jump Cancel is a mechanic that involves Jumping and Stepping to cancel a jump's vertical height

This can be useful to gain more momentum that normally possible, and makes jumps such as 1bm hh 5b possible.

Definitions:


 * The jump motion (0.42m) is the height of the first tick of a jump.
 * The step height (0.6m) is the highest step the Player can move onto without jumping.

Both values are hard-coded into the game, but they aren't always handled correctly by the game.

This makes it possible to use Jump Cancelling in unintended ways.

Slab Variant
This variant is intended, as it is the logical extension of Stepping mechanics applied to Jumping.

When walking up a step, the game attempts to place the Player correctly by:


 * 1) Setting their Y speed to 0.
 * 2) Setting their Y coordinate above the step.

In the process, the jump's vertical speed is lost, but horizontal speed is conserved. This makes it possible to jump again 2 ticks later.

This variant only works if the step height difference Δ is between 0.42m and 0.6m.


 * If Δ < 0.42m, the Player jumps above the step before the collision can be detected.
 * If Δ > 0.60m, there is a collision, but the step is too high to apply stepping mechanics.

Jump Cancel can be used to build momentum on stairs, amongst other blocks.

This is why experienced players spam space when moving up stairs.

Note: It is possible to use the corner of a slab to jump-cancel without moving up the step itself. To do this, the collision must be X-facing.

Ceiling Variant
This variant is unintended, and was patched in recent versions of the game.

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