Found some interesting settings that might help solve or reduce culling in Half Life Alyx without needing PP

I haven’t tried it yet on the StarVR. I’ll give it a shot later today!


@mixedrealityTV Okay, so I tested it out using the launch options. It works but with some glitches/tradeoffs.

When I set the value to 25, the culling is reduced on my right peripheral. When I increased it to 40, the main menu at the start of Half Life Alyx is not there. You have to move your head forward toward the menu. Then when you select a menu option, you have to again tilt your head forward until the new menu appears. At 40 value, once in game, objects were being culled right in front of me in both eyes, so I knew it was too much.

Next I tried value of 30 and this seems be a sweet spot. I still have to lean in closer to menus for them to show up, but the culling in the right peripheral is much further out of the peripheral. So it did improve it a lot! Some other downsides though are when I open the weapon menu, the weapon icons are shown but not the weapon ammo values, for that you have to move your head around a bit to make them show up. I also noticed from a far distance the bottles at the bar only appeared once I got to a certain distance. So it appears this frustum culling settings does not just affect the peripheral but also objects far in the front.

Personally I think I like Alyx better at the 30 value. But I think some other settings need to be changed to fix these minor problems. I’m going to experiment with other console commands and file settings.


Okay so I’ve found the best configuration is the following launch options:

-console -vconsole +vr_expand_cull_frustum 30 +vr_enable_volume_fog 0 +vr_main_menu_to_player_distance -40

First command will reduce object pop-ins on the right peripheral vision, however some objects from a far distance like bottles and cups on a table may not load right away until you get closer to them. This doesn’t happen that often so overall I’m very happy to have reduced on my right peripheral

Second command disables volumetric fog. In wide fov headsets like the StarVR One the fog seems too strong. Once I disabled it, the picture quality in HL: Alyx looks SO much better on this headset and the blacks look like they’re supposed to in this OLED headset.

Third command brings the main menu much closer to the player. When the game first loads, the menu will not be visible. You’ll need to stand at the feet mark and lean your head forward towards the menu for it to pop up. If you find your scrolling or selection doesn’t animate, you need to lean in again. When you select something from the menu, just lean in a bit for it to display too. This is the unfortunate tradeoff of doing the expanded frustum culling. Main benefit to this command, is that when I open the menu while in a game, it works perfectly fine without needing to lean in to it. So that’s why I offset the distance.

Let me know guys what these settings look like for you on Pimax or StarVR One. I have also tried 35 but that one made objects from a distance cull too close for my tastes. So 30 seems to be a balance. I’m currently trying to figure out how to fix the culling distance while leaving the first command enabled.


Good news, @VR-TECH @vrftw @crispybuttphd I found a built in command in Half Life Alyx for Mura correction. Just add

+vr_mura_correction 1

to the launch options from my post above. I think it looks better with mura correction and volumetric fog enabled. I wonder what you guys will think of the difference.


Iirc, that was controlled in HL2 by a different setting. It has nothing specifically to do with VR. I think it might be controlled by r_staticprop_lod.


I’ll look into that. So far I’ve tried

+r_occlusion_culling 0

Which disables distance culling altogether and it seems to have helped with most objects. I’ll have to do more testing. There is a slight performance loss with it disabled though. Like 75 to 90fps with slight jitters.

I suspect the reason why the more you expand the frustum culling FOV, the shorter the distance that objects get culled is, that the camera is looking through a triangle view. When you bendout that triangle, the FOV gets wider but the end of the triangle gets shorter. So that’s why I’m hoping another command or settings would disable distance culling outside of the camera’s view to some extent.

LOD stands for level of detail. Iirc it’s an integer additive offset, which controls the complexity of the model displayed for a given distance. That setting or a related one sets the distance at which a model is drawn (or not). Basically, it controls the complexity of the scene and allows distant objects to be drawn with less detail or hidden from view, until they get close enough to matter.

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So Sebastian, is the StarVR a loaner or a keeper?

Nice work man!! Currently My StarVR or Pimax give me error 108 with Steam VR. I’m prepping for my project. Hope I can sort out this out over the weekend


+vr_mura_correction 1

Really curious about that one. I’ll be trying tomorrow. Does it really reduce the mura on SVR1?

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Oh my god you guys! I’ve found the secret command that disables culling once and for all!

Use this in launch options:

-console -vconsole +sc_no_cull 1 +vr_enable_volume_fog 0

The last command is optional depending on if you like fog or not. After adding sc_no_cull, there is now absolutely no culling at all on my right peripheral vision! I have the full field of view and it’s incredible! The only problem left is the ocassional black smearing occuring on the right eye and that’s no big deal. Wow. I also did not notice any reduction in performance at all by turning off the culling.

@mixedrealityTV @VR-TECH @vrftw @crispybuttphd


You the man!!! That’s truly incredible, thanks for digging into this!


Do you think other games have this kind of launch options? It would be so cool if you could just change it like that!

@VR-TECH Nope, it’s still a loaner, but StarVR didn’t get back to me for a while, so I still have the device.


I take that you are also adding the Mura command?

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When I added the mura command, I don’t really notice a difference except maybe less clarity from a far distance. Maybe it’s just because I’m not sensitive to it like you and vrftw. So I’d like to know when you try it.

Many (most?) games have launch options, but it varies by game. Some only have minimal options, while others have extensive options.


I’m really wondering how different our units are… Maybe it’s because I also have a Pimax. I see mura on my 8k+ but 99% less.

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Awesome. It is possible there is some standard command line that is recognized by all games written with a certain engine, i.e. unreal or unity. If we could figure out the no_cull command line parameter for either of those engines, if there is one built in, that would be awesome indeed. For example, in terminator salvation you can use the parameter -vr to launch it in VR, but its kind of messed up when it comes time to shoot.

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Yes, I think it’s possible that other engines/games might have a similar command line. Half Life Alyx runs on the Source 2 engine built by Valve. I’m going to look into getting rid of culling in other games like Boneworks now. Either by finding a way to disable it or by creating a Unity project with StarVR’s frustum script, compiling the project and then doing a difference comparison between the same project with and without the script and then seeing if I can implement universally compiled files into Boneworks that way. Ideally I’ll try the easiest route first by finding command params, etc.


what’s really sad about this is that, we all saw the Pimax at Valve HQ when Norm from tested was claiming to have issues with what he was seeing with Pimax

Did Valve even actually use the Pimax to test at all! To think all they had to do is tweak so settings for Pimax headsets for it to work correctly.

It makes me think they didn’t test at all. Did you post this on Hl Altx forum maybe you can get them to fix this in the game so we don’t have to do it ourselves.