Users Phasing Through Terrain

Bug Reports Engine Bugs
#1

Reproduction Steps

This issue just began occurring in the last few hours.

Happens frequently when deploying here: đź—ľ UPDATE đź—ľ Rolling Thunder - Roblox


Expected Behavior

I expect when the server teleports your character onto voxel terrain to be able to interact with it normally.

Actual Behavior

For a few seconds after being teleported onto some voxel terrain, there’s a chance you’ll phase right through it. This seems to occur to any user on any level of hardware regardless of render settings.

As I mentioned it started happening just a couple hours ago, it also seems accompanied by significant performance issues that were not present in the previous roblox client build.

Workaround

No this has broken my game because users are just falling through terrain.

Issue Area: Engine
Issue Type: Other
Impact: Very High
Frequency: Often
Date First Experienced: 2022-12-11 07:12:00 (-05:00)
Date Last Experienced: 2022-12-11 00:12:00 (-05:00)

5 Likes
#2

Here’s a clip of it from my game’s discord. You can see that my server script has detected the fall-through and tries multiple times to put the player back up above the terrain.

1 Like
#3

might want to freeze the player for a few seconds before spawning them as it seems from the clip, once the player is teleported Roblox is trying to put the terrain as normal instead of using the LOD mesh.

Not really a bug, just Roblox’s LOD system doing its job.

#4

Workaround:
Start ray casting below the teleport area until it reaches the desired distance.

LOD should not affect terrain physics. This is clearly a bug.

1 Like
#5

This is how it is in AAA games, far away terrain has no collisions, no point running calculations, shadows, and having as many triangles on something that is far away, it is not a bug, it is for perfomance.

1 Like
#6

It would be nice if Roblox had a good way to render this stuff beforehand though.

#7

I also have this issue. It is very prominent on bad internet devices.

#8

It is most definitely a bug, this has only started happening recently.

You can very clearly see that the terrain in the video is at it’s best level of detail, and AFAIK terrain never loses it’s collision, even far away terrain, but I’m not as sure about that.

#9

I already do, you can see in the video the server is raycasting to determine where the terrain is, and setting the player above it multiple times.

#10

UPDATE:
This seems to be caused by server slow down, if the server frame time exceeds 20ms, users will begin phasing through terrain when the server uses “PivotTo” on their character, but not baseparts. The reason why this started happening more frequently in the past few hours is because in my latest builds I’m having the server do more work than it used to.

#11

Ive had this happen before, years at that, fairly old occurrence, only happened on my old pc while in studio, or devices with bad internet, so id assume it is mostly server to client.

#14

Thanks for the report! We’ll follow up when we have an update for you.

1 Like
#15

Hi there! Is this issue still happening for you?