Percieved scale in virtual worlds


A litttle while back I was looking at this article and podcast here, which among other things talks about how through VR one can be “inserted” into a body that is physically different than your own, and that the virtual world can be changed in apparent size in relation to being, say, in a smaller, child-size body.

In other words, if you’re trying to simulate being in a grade-schooler’s body inside a virtual house, the house would now be presented to you in the same perceived scale as a real house would be to a real grade-school child. The walls would seem farther away, the ceiling higher, the furniture larger, the doors bigger and the doorknob raised up higher, etc.

I do think somewhere along the line HiFi, when experenced through the goggles and virtual-gloves, needs to have a perceived-scale mechanism like that built into it, so that if I show up as a little-kid character, or for that matter show up as an anthromorphic housecat character who’s the size of a kindergartener, the world will seem suitably “oversized” to me, on an adjustable slider to match the av, maybe a value that’s stored along WITH the particular avatar, so that if I switch from the anthro-cat to, say, something resembling Lurch from Addam’s Family… the perceived scale instantly changes to where the house seems slightly too SMALL now. And if I switch to a King Kong or a Godzilla av… BOING! …suddenly everything’s dollhouse-sized! :smiley: :smiley:


A lot of this would be down to how high the camera is off the ground, for child vs adult. I don’t see how things (other than in the height plane) would seem further away to a smaller humanoid than to a larger one. Where the larger vs smaller AV fits would differ too, though that is simply the size of the capsule(s).

For much smaller, or larger characters, as well as changing the camera height, you would also want to change the inter-pupilary distance as presented to a HMD, but again, the world wouldn’t change, but the position from which it is perceived. And where the body will fit.

Also, how large a world feels would be effected by how quickly one traverses it. The mentioned Godzilla would have a logically greater-than average walking speed, while a small child would have a lesser one.

The main thing I use HiFi for at present is just loading in a landscape or structure and walking around it to see how large it feels, irrespective of its actual dimensions in metres. I am still working at ways to make a physically smaller space (less triangles) both look and feel much larger


It’s not about the scale of everything else. It’s all about where the camera eye is placed. I used to have (as did others) scripts that adjusted the camera to be based on the height of the avatar. So, tinies, for example, had their camera (both 1st and 3rd person) lowered to reflect their avatar’s true height.


As of the moment I feel short in every meeting I’ve been to as I’ve been running around as a character the size of 1.6m. this seems to only work for 2D screens (height of the camera )

However for HMDs I havent tested yet:

If it hasnt been done,
Other way is to simply measure the distance between the eye bones with scale taken to account per avatar taken: But the main issue there is that some heads shapes may have different distances.

However the main issue with this is that if you do have an avatar thats of a different size, the scale may seem skewed.

One way to solve this is simply to add “scale world according to avatar size” for HMD setting.


Pretty much what the first two are talking about here is more analogous to the placement of a camera in a movie, looking at one or more characters in a scene, with the view of the camera being perceived more from the perspective of a movie audience than it is from the perspective of the characters in that movie. This is why I specified the view from the VR goggles in particular, since that’s a different thing: you’re seeing it from the eyeballs of a particular character in the movie instead.

To illustrate what I was driving at… one thing I distinctly remember from when I was 5 years old was sitting on the toilet, and staring over at the little rug that was placed next to the bathtub towards the end opposite from me. (The toilet was right next to one end of the tub and was facing towards the wall at the opposite end of the tub.) That little rug had Yosemite Sam on it, and was fairly close to the wall over there. I remember how far away from me that rug seemed to be, since I was looking outward ACROSS the floor at it. And in fact, the whole bathroom seemed quite large across to me.

I live in the same house today, and while we’ve replaced the tub, toilet and sink in there, the layout of everything is still the same… but now that bathroom seems so much smaller, and in fact maybe a little cramped, now that I’m long since a grownup. On of the things that surprises me a little bit is that, when I’m sitting on the toilet now, is that the spot where that little rug was (the rug itself is actually long gone) is now right where my FEET sit, and the wall that was past the end of that rug is now close enough I can touch it… but when I was 5 that wall, and in fact the little rug, was well out of my reach and seemed to be far away from me.

Consider the movie “Fantastic Voyage.” In that movie, you see a submarine with a crew in it progressively shrunk down to microscopic size. The way they portrayed that, among other ways, was to show the room the sub was in become progressively larger and larger while the sub itself showed on screen as the same size (in relation to the screen, that is), while at other points showing the room as the same size as before (in relation to the screen that is) while we saw the sub getting progressively smaller and smaller until it shrank from view and could essentially be picked up with a pair of tweezers.

Now, imagine I was today standing in the tub, and was being hit with a shrink-ray like the one in that movie, and I’m being progressively reduced down until I’m back to the size of a 5 year old again. As this happens, I’m not only seeing the edge of the tub rising up taller until it’s a ways past my knees when standing, I’m also seeing the other end of the tub receding farther and farther away from me.

This is the effect I’m talking about. Can this sort of thing be simulated by merely moving the created left eye and right eye view closer and closer to each other? Would that be all it takes to have the end of the tub seem to recede markedly farther and farther away from me? Somehow I doubt it, but it would be interesting to see if that was ALL it took.


The other end of the tub won’t recede away from you, only your eye’s height off the floor. Even the change in inter-pupil distance won’t be that pronounced due to the somewhat asymmetric way human heads grow relative to their bodies. Any apparent change in scale in this case is largely psychological. The only thing that has really changed is distances relative to your (then shorter) reach, nothing visual. Keep in mind that the brain tends to work in relative terms, so this shortened reach is, psychologically, significant in effecting perception irrespective of reality. The far side of your Yosemite Sam rug (and the walls, cieling, etc.) was further away from your maximum reach and your perception at the time was set to work with this.

A Fantastic Voyage shrink (or 60ft Woman enlargement) would, however be a slightly different matter as it would significantly change the optic properties of your now-significantly-different-sized eyeballs. The effect would, however, still be in-camera (or in-eyeball if you like). Objects would appear to have different focal distances (and stereoscopic divergence) to what prior experience of their normal size would lead you to expect. Also as you moved about (taking into account your significantly different stride length and relative velocities due to your personal change in scale), they would exhibit different motion paralex to what you may be expecting. The brain would likely interpret all this as everything around you changing size, even though it is really you that has changed. Again, the brain tends to work in relatives, rather than absolutes (quite a lot of optical illusions work because of this).


That does not make much sense to me since the scale is always constant for a given optical camera/lens arrangement. it is an invariant. Just because an avatar is small means nothing more that if it is a land creature, its eyes are at a certain height. Things seem bigger or further away simply because of eye to object angles and distance.

Now it is the case that scale perception can vary but that has more to do with the size of the eyes or the lens apparatus. Eagle vision versus lemming vision, for example. But if anyone is referring to the size of a specific kind of creature morphology, let us say a human being, the scaling is invariant irrespective of size.

Here is a vid of what a one foot tall humanoid, whose eyes are 10 inches above the ground sees. Their eyes, being a tad smaller have a lower focal point, so using a phone’s camera is more or less about right.


Keep in mind, Nathan, no one is saying viewer perspective from a different-sized avartar’s eyes is not possible or very difficult… in fact it is far less complicated than you assumed it was! It really is just a positional and focal-length adjustment to the camera(s). And changing the size of the avatar’s body as experienced to match, of course.

Obligatory XKCD link