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poor fit and image warping for people with large heads?

erikm
Explorer
I've got a big head (62cm hat size) and even with the straps un-velcroed and the ends just sticking out sideways, there's more pressure than I'd like on my face. Experimenting with the facial interface on and off, I've also noticed it seems like the image warping that is done to correct for the lens distortion isn't correct for how far away the Rift sits from my eyes. With the facial interface in, if I turn my head side to side in Oculus home while being aware of (but not really focusing on) the vertical lines of the game icons and trees in background, it seems like the top corners warp inwards as they get close to the screen edge. But with the facial interface removed and my eyes a bit closer to the lenses this doesn't occur. It also feels like my FOV is less limited with the interface removed, I can see the side edges of the screens if I look straight forward, but with the interface in place my FOV is limited by the round curve of the lenses. My ipd is 65mm btw.
My plan is to try to get a more suitable facial interface 3D printed, so I'm experimenting with creating/scanning a 3D model of the original (and of my head) and modifying the interface to suit me better. So far I'm at the scanning stage. David Laserscanner wasn't working for me, 123D Catch looks like it generated more usable results, I'm waiting for ReMake to finish processing the same images to see if that does it better and I also have a xbone kinect sensor coming that I'll play with and see if that works...

I've seen other people mention getting better FOV by removing or reducing the thickness of the facial interface, but I haven't seen anyone mention incorrect screen warping before. 
11 REPLIES 11

CrashFu
Consultant
Huh. I've got a pretty big noggin myself, but not big enough to make the Rift fit poorly.

Good look in your modding efforts; I'm sure plenty of people would be interested to hear about or see photos of the results.
It's hard being the voice of reason when you're surrounded by unreasonable people.

Anonymous
Not applicable
The image warping is an issue if you haven't adjusted the headset properly in the vertical axis. Your eyes are basically just outside the sweet spot. Try ging back to the IPD adjustment screen with the green cross, and make sure the horizontal lines are perfectly crisp.

Or you could try sliding the headset up and down while in the home screen until it doesn't warp anymore.

I sometimes had the same problem, but after I found out what caused it it is very easy to fix.

brantlew
Adventurer
Vertical positioning is indeed crucial but eye relief can play a role as well.  The lenses and distortion correction are designed for optimal performance at about 12.5 mm eye relief - that's the apex of the lens to your cornea.  How do you measure it?  Here's a handy trick.  Take some coins and stack them until you have about a 10.5 mm (give or take) stack and then tape them so they don't fall apart.  Face the headset downwards and put the coin stack right on top of the lens.  Now close your eyes and gently put your head into the headset and try to match the correct foam pressure that you wear it at.  If the coins are just barely touching your eye lid then that's about the right eye-relief.  Don't be obsessive.  The lenses can accommodate some variance in eye-relief and facial structure.  But this is the ideal placement where chromatic aberration and distortion should be minimal.

PS.  If you are going to be obsessive about anything - do it for vertical placement.  That's the thing that is easiest to correct and can have a major impact on visual distortion.  Don't position your headset vertically according to where you think the foam should sit.  At all costs position it so that you are looking through the optical center.


agenttoff
Heroic Explorer
Yeah, I don't suggest you do any of that ^, although with how scratched up those lenses will be you might not notice the warping anymore.   🙂

brantlew
Adventurer
Back in the DK1 days, we used to have a DK1 with the front removed so that the lenses were exposed.  We had a flat screw drilled right through the lens and one person would wear it and another person would gently turn the screw until it touched your eye-lid.  Ghetto eye-relief measurement but it worked great!  But most people were too squeamish to endure it.  Felt like a medieval torture device.  🙂

erikm
Explorer
brantlew, thanks for that very informative post.  🙂

TwoHedWlf
Expert Trustee

brantlew said:

Back in the DK1 days, we used to have a DK1 with the front removed so that the lenses were exposed.  We had a flat screw drilled right through the lens and one person would wear it and another person would gently turn the screw until it touched your eye-lid.  Ghetto eye-relief measurement but it worked great!  But most people were too squeamish to endure it.  Felt like a medieval torture device.  🙂


That sounds like a very effective method...But...Uhh....I only trust a few of my coworkers to twist screws into my eyeballs...

erikm
Explorer
I just tested it with a piece of blu-tack stuck to the lens, it measured about 16.5 on the left eye and 15.5 on the right, so + 2mm that puts me at about 18mm eye relief.

Anonymous
Not applicable
Which means you should pull the headset tighter. 🙂