Small IPD Causing Issues - any Solution?

[Smidgy]

On some games (Elite Dangerous, for example), my Vive seems to display everything at too small a scale.  I strongly suspect this may be down to IPD.  The minimum that can be set in the Vive seems to be 60.8mm, but various methods of measuring my IPD seem to confirm mine is actually 54mm.  Is there any way of overriding the set IPD, or in some way compensating for this?

[HackPerception]

     Hi Smidgy, the IPD range of the Vive is mostly a reflection of the fixed lens design of the HMD which in turn is based on the average adult's IPD. Generally speaking, having an IPD range outside of the Vive's range results in blurriness and soft edges which can result in discomfort, not the type of scaling issues you described. That said, your IPD is within ~5mm of its low end so you should still be able to use the headset normally, albeit with a bit of blurriness. You may have something else going on with how your Vive is set up through SteamVR, Windows, or the specific applications in question that could be causing the scaling issue.  Can you describe what you see in a bit more detail? 

[Smidgy]

Well, the actual image is clear enough (a small amount of blurriness, but nothing major, and even that is fixed by upping the supersampling through SteamVR), but, in essence, the entire game world is too small.  For example, in Elite Dangerous, I look down, and the body's proportions seem too skinny and short, so it looks and feels like I'm inhabiting the body of a boy around 12 years old instead of an adult, but in a world sized to cater for kids instead of adults.  I also have a PSVR, and I can get the same effect in Resident Evil 7 if I deliberately set it up with a too-big IPD, which is why I suspect that is the problem here.  However, I had a go in Elite Dangerous in a Rift, and the scale seems right, though its minimum IPD (59mm) is still larger than my actual IPD.

[HackPerception]

     I wasn't able to replicate what you're preciving using a Vive set to ~15mm greater than my IPD but my eyes fall within the range designed for the Vive's fresnel lenses so I may not be physically able to personally replicate it. The PSVR has a standard lens design so I can't really speak towards it. I'm confused about why you would experince it in some apps and not others. Prehaps it's a combination of the interaction of your biological features (IPD, pre-existing vision conditions such as astigmatism or myopia) with the hardware that's leading to your werid preception issues. I'll look futher into this. What you're describing sounds similar to when you get a new pair of glasses and your brain has to readjust to the new input. Do you wear glasses and if so are you wearing them inside of the HMD? 

[Smidgy]

Nope, no glasses, and no vision problems at all.  From what I can see, with Elite Dangerous specifically, there have been reports of this issue on their forums, with Vive users falling into three groups:

 

1)  People who simply don't see this issue at all, even when comparing directly with the Rift, and wondering what everyone else is talking about.

 

2)  People who have found that deliberately mis-calibrating the floor level in SteamVR's room setup fixes this, for some reason (I have tried this with no effect).

 

3)  People who see the scale of the world changing by changing IPD.

 

I am not entirely sure this is entirely fixable on your end, as it may be down to how each bit of software interacts with the hardware itself.  I say this, because, by default, I get this issue in Project Cars as well - but they have implemented a 'World Scale' setting that fixes this without messing about with IPD.  However, if there is some config file or hack I can mess with that allows me to make the Vive itself change the world scale, I can use it on games I get this issue with that don't have their own solution.