Ladders are special blocks that allow entities to climb them.
Vines were added in Beta 1.8 and share the same properties, but have no collision.
Relevant Minecraft Wiki articles:
When attempting a ladder jump, you should always sneak at the end of the jump.
Don't sneak too late or you won't catch the ladder, but don't sneak too early either as that will slow you down before reaching the ladder.
Visually, ladders and vine appear as a flat texture, resting 1 pixel away from the wall it's placed against.
- In reality, ladders are 2 pixels wide (0.125b), 1 block high, and 1 block long.
- Vines, on the other hand, are intangible, meaning the Player can move right through them.
While the player's coordinates are within a ladder's voxel, vertical movement is affected in two ways:
- Colliding with any wall will make the player climb at a constant rate of 0.1176 b/t (0.12×0.98).
- Sneaking will prevent the player from falling.
Ladders also affects horizontal movement:
- Horizontal speeds (X/Z) are capped at 0.15 b/t
- Vertical speed (Y) has a lower bound of -0.15 b/t
- In 1.9, ladders were changed to be larger by 1 pixel, making their new bounding box comparable to trapdoors (3px in width, or 0.1875b).
- In 1.14, the player can now climb ladders and vines by pressing jump, which makes ladder jumps feel easier.