Parallel Projections & SteamVR Application Resolution Setting (ss) & FpsVR conclusion

Cpu : AMD-FX8350
Gpu : 1070
Ram : DDR3 16GB
Game : Battlezone

SteamVR Application Resolution (super sampling, ss)

  1. When you adjust this while playing the game (I adjust on steamvr setting), your fpsvr will change the value immediatly, but no any effect.
    If you adjust in fpsvr, in steamvr setting will not change and the game not change too.

  2. SteamVR Application Resolution will have effect to your game when you set this value before start the game only.


  1. You set ss at 100%, then you start the game
  2. You change ss to 20%, the game not change, but fpsvr will show 20%
  3. You change fpsvr to be 200% and now fpsvr will be 200%, ss will be 20%, game not change.
  4. You close and play game again, game will reference resolution from fpsvr (not ss), but when you change ss, the fpsvr will change to be same ss again.

p.s. Some game need to restart steamvr, some game you can change on fly such as space pirate trainer.

Parallel Projections
I set Pitool rendering quality at 0.75 (forget to change to be 1).

  1. Tick in PiTool - ss 100% 45 fps , more clarity.
    ss 500% 25 fps (Still can play).
  2. Not tick in PiTool- fps 60 , less clarity.

issue when you not tick this option, on game loading page before start game, wrong stereoscopic , have edge distion (can see on the monitor).

  • This need restart steamvr

Rendering Quality
Don’t misunderstand that
PiTool 1 , ss 100 = 1 x 100 = 100%
PiTool 2 , ss 50% = 2 x 50 = 100%

The Render quality of PiTool will use steamvr resolution to calculate.

If you choose resoltion 100% = 3852 x 3291 in steamvr.
Then you choose Rendering quality = 1 then you will get 3852 x 3291 resolution
Rendering quality = 0.5 then you will get 1925 x 1645 resolution. (When I test first, it is 1746x1645.5,but not sure why it change).

If you change steamvr to be 50% = 2724x2327
And you choose quality to be 1 then you will get 2724x2327 resolution

ss 100, pitool 0.5 --> 1925 x 1645
ss 50, pitool 1 --> 2724x 2327
As I said ss x pitool = 50%, but resolution is not equal and you will see that ss make more solution.

These are list
PiTool 1 , ss 100 3852x3291
PiTool 1 , ss 50 2724x2327

PiTool 0.5 , ss 100 1925x1645
piTool 0.5 , ss 50 1326x1163

PiTool 2 , ss 100 7740x6581
PiTool 2 , ss 50 5448x4653

PiTool 0.5 , ss100 1925x1645
PiTool 1 , ss 100 3852x3291
PiTool 2 , ss 100 7740x6581

piTool 0.5 , ss 50 1326x1163
PiTool 1 , ss 50 2724x2327
PiTool 2 , ss 50 5448x4653

You can check the resolution which headset using in steamvr setting when change PiTool Rendering and restart steamvr.


@bubbleball i am pretty certain that everytime you change PP or FOV you have to restart steamVR. Yes, you see that the picture is changing, but only because the aspect ratio changes, but not the resolution the game renders, unless you restart SteamVR. This is certainly the case with the FOV and SteamVR SS setting and I think it is the same with the PP setting.


edit : I restart steamvr every time when I test parallel projection.

Infact I test parallel projection before testing SteamVR Application Resotion, I swap content because I only want to reference the ss keyword.

About ss, I notice that only restart game has enough to change the resolution (not change PiTool Rendering quality because I test that for the last).

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PP is parallel projection :joy:

You can not just restart steamVR without restarting the game. And without restarting SteamVR, the game does not receive new values from SteamVR because it itself is not restarted. And SteamVR reads important information from Pitools.

Imho the chain of Information is like this:
So if you start SteamVR it receives critical values from Pitool (FOV/PP) it then applies its SteamVR SS setting on top of it. The application asks the resolution it should render from SteamVR.

Only question for me is when a ingame SS setting like in ED) is applied. Before SteamVR SS setting or afterwards. Or even game specific…

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Just understand later about pp and I already edit my post.

My test is

  1. Parallel projection --> restart steamvr
  2. SteamVR Resoltuon & FpsVR --> restart game only because not change any value in PiTool (This test about on fly setting only and different value between FpsVR and SteamVR).
  3. PiTool Rendering Quality -->restart steamvr.

My experience is that you have to restart steamVR if you change any SteamVRSS setting. FpsVR just mirrors the SteamVR setting, but the application does not receive the new values unless you restart steamVR. I tried to dial down the SteamVR SS Settings from 100% to 25% andcrestarted the Game. But the picture was the same. I had to restart SteamVR to take effect.

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Okay, may I will test again.

Last test I just only return to steamvr home, change sampling and start game in steam home. The resolution is changed.

This test only want to know that ss still have effect to the game.

When I ever use riftcat, it has resolution in application, I can change it immediatly to see the resolution.

When I test space pirate trainer, when I change ss, the font is more jaggy or more smooth.

So I only suspect that this ss still effect to the game or not, so restart steamvr or game not a main point. Only check how it work.

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You SAW the change or only saw the report of fpsVR? Because fpsVR just displays the reported settings of SteamVR…

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Fpsvr value is change immediatly, graphic will change when restart game.
I test ss 100 and 20 to see that the graphic is changed.

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Then maybe it is different from game to game. When I tried with subnautica, restarting the game only did not change the ingame resolution.

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Maybe, so I will note more in first post.

I can set ss on fly with space pirate trainer, but not sure because Riftcat software or not. May I try it later.

Yesterday, I play The rose and I and I see that image look better when I change by fpsvr.


I already try space pirate trainer, it can change the resolution immediatly without restart game or steamvr.


Game SS is applied to the final res, as determined by PiTool and SteamVR.

Parallel Projection issue list.

If you not tick this option I found that.

  1. Battlezone, the edge will have wrong distortion.
  2. Fruit ninja, the object at the edge will have delay rendering.

Not sure what engine they are using.

Will update if find more.

I thought PP was Planned Parenthood?? :grin: