PBR and Depth Perception

[Iyoba Tarantal]

For nearly all my life, I've had no depth perception. To me Second Life has always looked as three dimensional though not as detailed as "real life." Photographs also appear three dimensional to me. Recently I read about PBR textures and how to make them, and I saw an illustration of one and may have seen another one on a new sim. Let's just say I was underwhelmed. The PBR lantern was a different color, but both it and the Bin-Phong one looked about the same. When I saw a shiney Tori gate on the new sim. It looked a bit weird, but not particularly shiney. I guess I feel disappointed. Note: I'll get the illustrations of what I saw and put them in here, when I get a chance to snap some pictures. Is it possible that I'm just going to never seen PBR the way everyone else does? As someone who "does great" with anything on a screen, I did not know PBR had accessibility issues. Does it?

Edited October 6, 2023 by Iyoba Tarantal

[Qie Niangao]

3 hours ago, Iyoba Tarantal said:

Note: I'll get the illustrations of what I saw and put them in here, when I get a chance to snap some pictures.

Please do because it may help convey what you expected that's different from what you experienced.

Somewhere in a Linden page describing PBR it makes clear that most of what the new materials do can also be done with legacy "Blinn-Phong" materials, but that older approach is less compliant with standards and uses more idiosyncratic creation workflows. Reflections are very different in PBR, though, and some much more subtle things.*

Users will most appreciate that new creations will more uniformly support at least one of these material systems because everybody using a soon-to-be current viewer will be able to see those materials, the non-ALM rendering path being disabled. 

Thing is, I'm not sure how much any of this relates to depth perception. Material effects can really only be appreciated when the camera, the object, or a light source moves. Put another way, none of this has any unique effect on static 2D scenes. (Reductio ad absurdum: Imagine a screenshot of a materials-bedazzled scene, painted on a canvas the exact size of the display from which it was captured. If nothing moves, it's indistinguishable from the original.)

So… PBR was never going to enhance depth perception appreciably beyond the best that could be done with Blinn-Phong, and any such effect would always be based on motion of something in the scene setup… and if that doesn't lead a particular observer to perceive depth in the scene, I doubt PBR offers anything to qualitatively change that. 

All that said, somebody who actually knows something about this "photos appear three dimensional" experience of depth perception might have a much more useful response.

_______________
*My favorite obscure advance: The new materials have a whole separate emissivity map, whereas in the past, emissivity was coded on the alpha channel of the diffusemap, which meant partially transparent surfaces were limited to fullbright or not emissive at all.

Edited October 6, 2023 by Qie Niangao

[animats]

50 minutes ago, Qie Niangao said:

The new materials have a whole separate emissivity map

What you're supposed to do with PBR is have lots of lights and realistic surfaces. Unless it's an illuminated sign or a disco, very few surfaces should be emissive. The big change with PBR is that you need to light the interiors of all buildings, or you can't see anything. A problem is that SL lights don't have real lumen ratings yet. PBR still has lights from 0 to 100 of something. They're supposed to be real light values, the sun should be far brighter than most lights, and you need tone-mapping to give the effect of auto-exposure. All the heavy machinery (PBR, tone-mapping, high dynamic range in the image) for that is in SL but it's not exposed to creators yet. Once this all works, SL should look like Cyberpunk 2077, which has all that. It's very striking when you go from a dark room to bright sunlight. Just like real life. Which is the whole point.

PBR doesn't change illusion of depth. We had normals with ALM (although too many objects don't have them), and we have normals with PBR.

Please try to hold down the use of shiny with PBR. Go visit Materials 1 on the beta grid with a materials viewer, or Rumpus Room on the main grid. Ooh, shiny thing! Cool for ten minutes, then ugly.

[Qie Niangao]

2 minutes ago, animats said:

Unless it's an illuminated sign or a disco, very few surfaces should be emissive.

Right, and those usually can be done with simple fullbright, no need for variable emissivity. Some things, though, need it. The surface of a lit candle, for example, emits light from the flame glowing through the wax. For that, an emissive alpha mask was adequate because the wax is opaque. Flames themselves, though, are transparent, and also emit with spatially varying brightness which in the past we had to fake by making them full bright and just darkening them wherever they should be emitting less; that's one place the separate emissivity map helps increase realism.

I did say it was obscure.

[Love Zhaoying]

I almost paged @animats when I saw the post!

[Iyoba Tarantal]

What I suspect is that my mind usually adds what my eyes don't see. This works well for objects that move at human speed, slower, or not at all. I don't even know I'm doing it. My compensation system breaks abruptly with either fast moving objects (No I don't drive!) or a major change in terrain (I grew up in the Northeast and live in the Southeast...all of which are hilly. I had trouble judging how far away a bus was in Columbus Ohio and the flat terrain of Boca Raton Florida felt absolutely infinite. After a day or two, my brain adjusted.)  My thoughts are that the reason both lamps in the SL picture look three dimensional to me is that I'm adding something to the first one, that people who see something missing in photographs don't add.
 

The Tori Gate on the new sim, may be suffering from too much lighting. I tried it both in my personal sky and with the shared environment.

My big worry with lighting in Second Life is getting stuck in the dark. I don't really worry about object reflections. That said, it might be fun to make a really richly textured wood. I did download Substance Painter.

 

[Ardy Lay]

4 hours ago, Iyoba Tarantal said:

My big worry with lighting in Second Life is getting stuck in the dark.

I suggest keeping a functional flashlight in your inventory.  I have seen some interesting art installations and games where one must use a flashlight.

[Wulfie Reanimator]

9 hours ago, Qie Niangao said:

All that said, somebody who actually knows something about this "photos appear three dimensional" experience of depth perception might have a much more useful response.

My understanding (with absolutely no prior experience about this disability) is that they don't "see photos as three dimensional," but rather 3D and 2D are indistinguishable to them, similar to a color-blind person saying "red appears green to me."

But yeah, I'm pretty sure PBR doesn't have any downsides in this case. It's just a different way of getting the same result. The two lanterns look different because the other one is reflecting the dark grass from the ground.

Edited October 7, 2023 by Wulfie Reanimator

[Jenna Huntsman]

10 hours ago, Wulfie Reanimator said:

The two lanterns look different because the other one is reflecting the dark grass from the ground.

That, and the viewer that screenshot was taken on was an older build of the PBR viewer, so doesn't reflect the current state of the PBR viewer (Source: am the person who took that screenshot)

[Love Zhaoying]

12 hours ago, Ardy Lay said:

I suggest keeping a functional flashlight in your inventory.

Or, just use your cellphone. They all have flashlights now!

[Charlotte Bartlett]

On 10/6/2023 at 2:50 PM, animats said:

What you're supposed to do with PBR is have lots of lights and realistic surfaces. Unless it's an illuminated sign or a disco, very few surfaces should be emissive. The big change with PBR is that you need to light the interiors of all buildings, or you can't see anything. A problem is that SL lights don't have real lumen ratings yet. PBR still has lights from 0 to 100 of something. They're supposed to be real light values, the sun should be far brighter than most lights, and you need tone-mapping to give the effect of auto-exposure. All the heavy machinery (PBR, tone-mapping, high dynamic range in the image) for that is in SL but it's not exposed to creators yet. Once this all works, SL should look like Cyberpunk 2077, which has all that. It's very striking when you go from a dark room to bright sunlight. Just like real life. Which is the whole point.

PBR doesn't change illusion of depth. We had normals with ALM (although too many objects don't have them), and we have normals with PBR.

Please try to hold down the use of shiny with PBR. Go visit Materials 1 on the beta grid with a materials viewer, or Rumpus Room on the main grid. Ooh, shiny thing! Cool for ten minutes, then ugly.

I have been testing a bit,  but interesting on interiors - when I create the house I can manage that well.   When people start adding in their own lamps, (face lights - LOL we know somebody somewhere still is doing that ha), scene management is going to be interesting.   I did not like leather results I did on furniture so more focus there needed to figure workaround.

I need to get more testing in too for my window glass as that is where I am seeing good results so far.