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MC-268535

The distances some entities travel are miscalculated

The distances some entities travel seem to be wrongly calculated. The affected entities (that I found) include Primed TNTs, Falling Blocks, Minecarts, Players, Items and most mobs. Unaffected entities include Snowballs, Arrows and Boats. Instead of following the equation s=vt (where s is the distance the entity travels in one game tick, v is the velocity of the entity in that tick, t=0.05 seconds which is 1 tick), it seems like s=kvt, where k is a constant that depends on the type of the entity.

Steps to reproduce

  1. Teleport yourself to a high place: /tp @s ~ 300 ~

  2. Summon a primed TNT entity with a very long fuse (so it doesn't explode): /summon tnt ~ ~ ~ {fuse:30000}

  3. Freeze the game: /tick freeze

  4. Get the y-coordinate of the TNT in millimeters: /data get entity @e[type=tnt,limit=1,sort=nearest] Pos[1] 1000

  5. Step 1 tick: /tick step 1t

  6. Get the velocity of the TNT in millimeters per second: /data get entity @e[type=tnt,limit=1,sort=nearest] Motion[1] -20000

  7. Repeat step 4

  8. (x)When you multiply the velocity in step 6 by 0.05 seconds, you don't get the difference of the two y-coordinates in steps 4&7

In the video, I summoned a TNT with an initial velocity of 39.2m/s (downward). This is its terminal velocity, which is the velocity that makes its gravity and air friction entirely cancel out, so its velocity is always 39.2m/s. It should move 39.2m/s*0.05s=1.96m in one tick, but it moved 2.00m. Ignore the scoreboard in the video.

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Attachments

Comments 2

Can confirm in 24w37a.

Thank you for your report!
After consideration, the issue is being closed as Invalid.

This report does not describe a bug.

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2511425938514

(Unassigned)

Confirmed

Entities

entity

1.20.4, 24w06a, 24w07a, 24w11a, 24w12a, ..., 1.21.3, 24w45a, 1.21.4 Pre-Release 2, 1.21.4, 25w03a

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