How to get rid of Shadow culling and fix volume fog in Half Life Alyx without parallel projection!

Hey guys, so in my previous thread here:

I was able to get rid of 95% of rendering issues in Half Life Alyx without parallel projection. The only issue left was that in the far right peripheral vision, some object shadows would pop in and out. This rarely happened but was still a little distracting.

Well I’ve found the solution to get rid of that. Add the following to your launch options:

+vr_shadow_map_culling 0

So the final line will look like this:

-console -vconsole +sc_no_cull 1 +vr_multiview_instancing 0 +vr_shadow_map_culling 0 +vr_enable_volume_fog 0

If you notice that the shadows of objects are still popping in and out of your right peripheral vision, it means that the value has probably been reset. It seems you might need to re-enable it each time you play a new map or save slot. To do that pause the game, and then on your computer press the tilde key (~) to open up the console. Under Command section type vr_shadow_map_culling 0 and hit enter.

Now Half Life Alyx looks 100% perfect. With the exception of volume fog looking weird/too bright if it is enabled. Maybe I’ll figure out how to make fog look normal, but for now I think having volume fog disabled is preferable as it gives deeper blacks to environments and improves performance.

I just figured out how to make volumetric fog look normal.

+volume_fog_enable_stereo 0

So if you want volume fog in the game, the final line will look like this:

-console -vconsole +sc_no_cull 1 +vr_multiview_instancing 0 +vr_shadow_map_culling 0 +volume_fog_enable_stereo 0


Just solved the volume fog issue too!


So finally there are no visual glitches at all with the star vr one in this game ? :heart_eyes: :star_struck:


And with a Spanish keyboard? The key in the same position, or the key with the (~) symbol (Alt GR + “4”) doesn’t work.
Anyone knows?

( briefly switch the keyboard to English and ) take the position of the key.

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You are the MAN! Excellent work! Just in time too before my 8KX arrives (hopefully in 2020 :smirk:).


Have you actually looked at the framerate to see if you’re getting better performance with all this disabled vs with PP on? When I tried it on my 8K X I was getting worse performance and it didn’t look any better than with PP on.


Any other way that doesn’t force me to install a language just for that, if it even works?

You don’t have to install anything, just change the layout of the keyboard in the settings.

For me (german) win+i , key layout.

I couldn’t do a comparison because I don’t have a Pimax headset. My 8KX is on pre-order. I tested this on the StarVR One and it ran smoothly.

When you compared my method vs parallel projection, did you disable the game’s auto fidelity system first and set it to level 3?

I didn’t disable the auto fidelity but with all the disabled items you mention it looked like it was at a lower fidelity if anything and ran around 50-60fps instead of the 75 the PP on was running at.

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Hmm, I see. Okay, well thanks for doing the test. I will do my own tests when I receive my 8KX. The main benefit of this will be for StarVR One owners like myself since that headset lacks a parallel projection feature. I get a smooth 75fps in the StarVR with those settings in most maps.

I tried on my 8k and it’s better than all other settings (pitool ss 2.0 (1.0 before pitool alyx version), steamvr ss 100%, large fov, auto fidelity disabled) -> 4908x3116


Nice work @NextGenVR :beers:


Where do you disable the auto fidelity setting, and what do I set to level 3?

The full parameters string I use:
-console -vconsole +sc_no_cull 1 +vr_multiview_instancing 0 +volume_fog_enable_stereo 0 +vr_fidelity_level_auto 0 +vr_fidelity_level 3


Just curious, what about using lvl 4?

level 4 is greater than ss 100%

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why not using 90hz of the star vr one ?

You can. I just decided to do 75Hz because the lower refresh rate, the higher Alyx’s auto fidelity system improves the graphics and I prefer resolution over refresh rate.