PaperMC / PaperMC/Paper

Minecart jitters when riding

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#12,464 8 comments 0 reactions 0 assignees View on GitHub

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status: accepted version: 1.21.5
Dominant language
Java
Stars
12.7k
Forks
3.5k
Avg merge
3d 13h
Merged PRs (30d)
11

Description

Expected behavior

Smooth movement of minecarts

Observed/Actual behavior

Minecarts rubberband for the rider.
The rider's view also rubberbands.

Rubberbanding is not visible to external viewers or when spectating the rider or minecart.

The severity of the rubberbanding isn't consistent. Reconnecting doesn't change it but restarting the server does.

Steps/models to reproduce

Ride in a moving minecart. Going in a straight line makes it more obvious.

Vanilla and spigot are NOT affected.

Fresh server on localhost.

MSPT between 2 and 10.

Plugin and Datapack List

None

Paper version

This server is running Paper version 1.21.5-23-main@5f0b829 (2025-04-19T19:56:53Z) (Implementing API version 1.21.5-R0.1-SNAPSHOT)

Other

Spotted by another user on discord:
https://discord.com/channels/289587909051416579/289587909051416579/1363681671731351762

Contributor guide

Open the contributing guide

First steps

  1. Read the whole issue, then the project's contributing guide.
  2. Comment on the issue to say you are picking it up — it saves two people doing the same work.
  3. Fork the repository and make your change on a branch.
  4. Open a pull request that references the issue number.

Research direction

Start by reproducing the jitter on Paper 1.21.5-23 using a fresh localhost server and a moving minecart, especially in a straight line. Compare the behavior with vanilla and Spigot, and verify that restarting the server changes the result. Done means the rider and rider's view move smoothly without rubberbanding.

Written by the indexing model from the issue text.

Assessment

Tech stack
java
Domain
backend, game-dev
Issue type
Bug
Difficulty
4/5
Estimated time
3-5 days
Activity status
Stale
Clarity
Mostly clear
Newbie friendliness
35/100

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