Scale translation and Height from Meatspace to Virtual and the avatar IK


So, you guys know that I run around in a short anthropomorphic avatar, around 150 cm if counting the ears, slightly less than 5 feet.

Thats fun an all, but there are issues when it comes to HMDs usage and positional tracking of height:

One of the first issues I’ve noticed time and time again is that we have no ability to calibrate our virtual scale to the scale in real life. In Meatspace, I am actually 183 cm, or around 6 feet tall. This means when I am mapped to my 5 feet tall avatar, with the estimated positions of my feet are 1 feet below the ground as everything is calculated from the head and down.

So, when I sit down on the ground, I’d be a head sticking out of the ground, and due to the IK, my feet would go all over the place, instead to a correct degree if my avatar was of the correct height. Even squatting 1/4 of the way to a full squat would cause my IK to go all over the place. That is, unless the avatar is the same height as me in RL. (I will get to that, someday :slight_smile: )

You can also simulate the reverse of this this by sitting down on a chair, and then moving with the controllers when using the HMD. Your avatar will pop up from the squat as it is bounced from the ground.

Some of the other experiences I’ve seen IK in, such as Hover junkers actually ask you to look straight before going into the experience to confirm ones height to map everything correctly. Maybe we should have the same in High Fidelity when we change an avatar?

As a side note:
Estimated hand positions are feel to be mapped one to one, but the virtual hand positions may go off at some points, because the avatar skeleton doesn’t match ones own physiology. This is fine, and there is some tolerance to it, as we all have different arm lengths and that is harder to calibrate than just height. That is, unless you scale your avatar up or down to extremes, when the positions of hands are still the same, meaning if you make your self large enough or small enough, your hands are where they arent supposed to be.


Is this one of the reasons why things in HMD look better and when am back in desktop mode my camera seems way to high placed ?

It’s something i start to notice more, my desktop my feels to be higher then then HMD me. In my case i think the height is pretty compatible with RL.

For my feeling i would like to adjust the DESKTOP Y-Camera position a bit lower.


Yes, this is a good example of the tyranny that drives the efforts to achieve hyper-realistic behaviors. That was necessary to get that tech working, but unless we create avatars that are scaled 1:1 in dimensions and exactly bone proportional, things fall apart. What is missing in the motion and position capture phase is a mapper step: from your own bone ratios and physical dimensions to the avatar’s bone ratios and its dimensions. When the tinies arrive, they will not be happy if this is not fixed. They will be ankle biting all the devs :fearful:

Somethng similar should be considered with positional movement. It too is presently 1:1 but we should be able to specify different ratios. I can see that in some worlds, a ratio of 1.5:1 (Vmove:Rmove) could be very useful.

Article: The issue with VRspace vs Tracking Space

Yeah, I imagine the kid-avs will have similar issues to the tinies, tho not quite to the same degree as with the tinies since the kid-avs won’t be quite as small.