Subscribe to download
Cable Performance Fix [OBSOLETE ON BETA BRANCH]

If you've installed any amount of mods for Black Mesa using the /custom/ folder method, then chances are you're familiar with this bug. Namely, in the second map of On A Rail in particular (bm_c2a2b), there's a massive performance hit when you press the button to raise the rocket platform.

While it's been known for a while that the problem was somehow due to the cables on the platform, as best I'm aware, no one was entirely sure why. I suspected it was related to the newLights casting shadows from the ropes, but that turned out not to be the case.

Turns out - the problem is that when cables are moving (at least when they're parented to another entity), the engine automatically searches for and loads a corresponding _back.vmt material for the rope in question. Usually, this works fine - but in Black Mesa, its new cables don't have corresponding back materials. This causes the file system to waste loads of time attempting to load files that don't exist, which causes a huge performance hit. This doesn't appear to cause any visual bugs, or spew any errors about the materials being missing, which is likely why it went undiagnosed for so long.

This mod is a very quick fix that simply copies the existing cable materials and adds the _back suffix to them. This alone makes a dramatic difference in performance in a handful of maps in Black Mesa. Note that in some cases, such as c2a2b, there's still some heavy filesystem usage - this appears to be a similar bug, though I'm not sure what precisely is causing it and my quick and lazy attempt at fixing it didn't make a difference. Even so, fixing the cables is enough to bring the framerate in a heavily-modded install from ~20FPS to 75-80.

This should fix any cable-related performance issues in both the vanilla game and mods.

Special thanks to narkvic in the CC Discord for inspiring me to investigate this!