I recently published a custom ball race map, which works perfectly fine in singleplayer, but becomes extremely broken in multiplayer. The issues I found are:
Boost Volumes with an upwards direction only work for the host (or, aren’t there for the other players)
The metal melon physics object (which are supposed to be extremely heavy) get flung at high speeds when players other than the host collide with them. (I also found that the physics objects were not spawning in correctly in multiplayer, but I’m unsure if that is correlated or not)
Steps to Reproduce
Play a ball race custom map with physics objects and an upwards boost volume in multiplayer while you are not the host.
What I expected to happen
Boost Volumes with an upward direction would properly lift the player upwards, the same way they should in singleplayer.
Metal Melons would not be able to be moved or “flung” by players colliding with them, along with them spawning in correctly just like they do in singleplayer.
What happened
Boost Volumes with an upward direction only worked for the host of the multiplayer game.
Metal Melons were flung at high speeds when any player would collide with them (unsure if this applies to the host too), and metal melons would consistently get stuck in their spawn locations by being stuck inside of other objects.
Notes / Media
These issues were found playing my ball race map “Downtown”, the map works perfectly in singleplayer but has these issues in multiplayer.
I’m unsure if this was a one time occurance, but I wanted to report these issues due to them severly making many levels in my map unplayable. If the map gets unit approved as well, these issues could allow for some unfair times to be set on the leaderboard. I’ll attempt to continue to investigate more into these bugs.
Players stuck unable to travel upwards due to the boost volume not working:
I played this map with a friend and had a blast - awesome map by the way! It’s really fun!
I am glad to know that you were using a Boost Volume, because I was thinking maybe the Push Volumes were being used and was gonna look into that. I’ll run the map in editor and figure out why the Boost Volume is desynced, along with the movers you have setup.
Glad to hear you enjoyed it, I spent a lot of time on it so it’s very rewarding to see people playing it and enjoying it!
Good to know you experienced the same issues as well considering I wasn’t sure if it was a one time event or not. Hopefully you can find out what’s being weird with the boosters and physics spawners without any issues, I’ll try to see if I can discover any causes on my end.
Another big desync bug was found. Level 10 on my custom map has movers that move back and forth while using “Rotate To” to rotate an object around (it’s the big group of planks moving back and forth). In multiplayer sessions, whoever is not the host will randomly get huge bounces when rolling across the rotating planks. In singleplayer, you roll across them without gaining any air, but in multiplayer you randomly gain massive amounts of air time.
Edit: This can also happen with other moving objects, depending on how laggy the host is. Not sure if there’s a true fix for this necessarily, but this bug may create a lot of unbeatable records.
Updating this thread since the boost volume bug (which was due to the volume being a cylinder) has been fixed. The two other issues I mentioned in this thread are unsolved, those issues being:
The metal melon physics object desync
Mover desync with rotating objects using “Rotate To” (or, just general mover desync)
Bumping this really old thread, physics objects in ball race custom maps are still extremely bugged. They now correctly spawn in on the host’s side, but are extremely buggy on all the other player’s clients. On top of them spawning incorrectly and interacting with non-host players in a way to make unintended collisions between a player and a physics object possible, sometimes a physics objects spawner will spawn more than the maximum object count.
