Falling/clipping through ground

[Yasand123]

Describe the bug
Upon starting a new game and loading the map the character (you) falls through the map. It looks like as if there's no ground, it's transparent.

To Reproduce
Steps to reproduce the behavior:

1. Launch CoP
2. Start a new game
3. Bug occurs

Expected behavior
Ground should load, character should not fall.

Screenshots, videos

BugTrap error report
It doesn't crash, there are no reports

Desktop (please complete the following information):

• OS: linux 6.18.2.arch2-1
• OpenXRay build version 1.6.02_83e025372 (just built it from source)

Additional context
I got the data folders from an exiting and working (preinstalled) GOG game. So I didn't need to extract anything. I doubt that's the issue.
I made sure the folders are lowercase when copying.
Other models load fine, like the gun.

[Xottab-DUTY]

@AMS21, @Masterkatze, @eagleivg, do you have any ideas, guys?

[Yasand123]

Update, I did g_no_clip 1 to fly up, and disabled it there. It seems some areas have collisions and some don't.

Here's a video demonstrating this: https://streamable.com/lj68r0

Also noticed when I quick load, the heavy breathing accumulates.. Not sure if it's related could be a sign of a bigger issue that would explain both symptoms. But for the main issue, ground collision doesn't match the mesh.

[eagleivg]

Try execute command rs_wireframe on in console and view static ground mesh in the hole place. (For run this cmd need build engine without MASTER_GOLD)

[AMS21]

Okay so I've been able to replicate this bug once on 83e0253 with a Release build. Just like OP I started a new game and immediately fell through the map.

I then tried to bisect when this started since I've never had this bug before but I was not been able to get the bug to happen again including on the original 83e0253 commit after this.

So I'm really not sure what could cause this or why