10th April 2011, 6:53 PM
You seem to completely misunderstand how your own visual system works.
If you are going to argue you can see the "backs" of things in the real world because you can go to the other side, that's also true of objects in video games. If you can rotate the camera, you can look at the back of a block there too.
This has no bearing at all on how you see objects in 3D though.
Let me explain. Your eyes aren't magic. They don't have the ability to intrinsically "know" the 3D attribute of something. It must be inferred from visual cues. The biggest cue we have (but not the only one) is binocular vision.
When you look at something with just one eye, all you see is a 2D image. Yes the world outside is 3D, but all your eye ever receives is a 2D image of that 3D world. The light enters your eye and hits your retina, which is a 2D surface. Your optic nerve does a little preprocessing and then sends this data to your brain. Your brain then attempts to discern what things are using other visual data. It is very complex. The only way you can even tell where one thing starts and the next thing begins is through visual processing. The same is true of 3D. Part of the way it is able to put together 3D from this one 2D image is from outlines. When one outline is interrupted by another outline which remains consistent and unbroken, the brain makes the assumption that it is because that second object is in front of the first. This can lead to optical illusions if you know this. It's how you can have "impossible shapes" like the following.
<img src="http://upload.wikimedia.org/wikipedia/commons/thumb/8/81/Impossible_cube_illusion_angle.svg/582px-Impossible_cube_illusion_angle.svg.png">
Due to this particular method of gathering 3D from the 2D image on your retina, it assumes that this is a 3D shape (when in fact it is a 2D illustration), but due to how the lines interrupt each other, it makes two contradictory assumptions about the shape, and the object thus looks impossible.
Another method used to get some 3D data from a 2D image is relative size. This is based on your existing internal database of objects, gathered by experience in life up to that point. In other words, when you have an idea of the size of people, and the fact that they are consistent, the brain can assume that if a small person is standing next to a tall person, and the dimensions are sufficiently exaggerated, and the feet of the smaller are above the feet of the farther, it is because one person is standing much closer than the second. However, again this is a quick assumption our brains make that is true enough to be usable, but can be manipulated in another illusion.
http://www.visualillusion.net/Chap07/Page01.php
Here is an entire class of depth perception illusions. This is caused by the fact that our brains have to cobble together our awareness of 3D from 2D images.
This brings me to the final point. Binocular vision just means using 2 eyes, but if you want the word used for our ability to combine the two images to form a 3D idea of depth perception, here it is.
http://en.wikipedia.org/wiki/Stereopsis
This explains in detail how it works. Not all animals can do this. Birds have their eyes located on the sides of their heads. They have a huge visual range, a panorama if you will, but lack stereopsis because the images from their eyes don't overlap. As a result, they can't use that method for depth perception and are strictly reliant on the other cues I mentioned. They seem to do pretty well for themselves though, except when they fly into buildings.
Do your homework next time. Our individual eyes see strictly 2D images. The world may be 3D, but our senses are limited. Just because something HAS an attribute doesn't mean our eyes can magically detect it, there has to be some mechanism in our eyes that they can use TO detect it.
If you understand that mechanism, you can manipulate it to feed it all sorts of data in the form of illusions. The 3DS and all 3D technology uses EXACTLY the same mechanism that our eyes normally use to process two 2D images into one 3D image. It works in the same way and, to our brains, is indistinguishable from the real thing. Explain specifically why that shouldn't be the case. Also, keep that quote. It should remind you to not make assumptions and do proper research.
If you are going to argue you can see the "backs" of things in the real world because you can go to the other side, that's also true of objects in video games. If you can rotate the camera, you can look at the back of a block there too.
This has no bearing at all on how you see objects in 3D though.
Let me explain. Your eyes aren't magic. They don't have the ability to intrinsically "know" the 3D attribute of something. It must be inferred from visual cues. The biggest cue we have (but not the only one) is binocular vision.
When you look at something with just one eye, all you see is a 2D image. Yes the world outside is 3D, but all your eye ever receives is a 2D image of that 3D world. The light enters your eye and hits your retina, which is a 2D surface. Your optic nerve does a little preprocessing and then sends this data to your brain. Your brain then attempts to discern what things are using other visual data. It is very complex. The only way you can even tell where one thing starts and the next thing begins is through visual processing. The same is true of 3D. Part of the way it is able to put together 3D from this one 2D image is from outlines. When one outline is interrupted by another outline which remains consistent and unbroken, the brain makes the assumption that it is because that second object is in front of the first. This can lead to optical illusions if you know this. It's how you can have "impossible shapes" like the following.
<img src="http://upload.wikimedia.org/wikipedia/commons/thumb/8/81/Impossible_cube_illusion_angle.svg/582px-Impossible_cube_illusion_angle.svg.png">
Due to this particular method of gathering 3D from the 2D image on your retina, it assumes that this is a 3D shape (when in fact it is a 2D illustration), but due to how the lines interrupt each other, it makes two contradictory assumptions about the shape, and the object thus looks impossible.
Another method used to get some 3D data from a 2D image is relative size. This is based on your existing internal database of objects, gathered by experience in life up to that point. In other words, when you have an idea of the size of people, and the fact that they are consistent, the brain can assume that if a small person is standing next to a tall person, and the dimensions are sufficiently exaggerated, and the feet of the smaller are above the feet of the farther, it is because one person is standing much closer than the second. However, again this is a quick assumption our brains make that is true enough to be usable, but can be manipulated in another illusion.
http://www.visualillusion.net/Chap07/Page01.php
Here is an entire class of depth perception illusions. This is caused by the fact that our brains have to cobble together our awareness of 3D from 2D images.
This brings me to the final point. Binocular vision just means using 2 eyes, but if you want the word used for our ability to combine the two images to form a 3D idea of depth perception, here it is.
http://en.wikipedia.org/wiki/Stereopsis
This explains in detail how it works. Not all animals can do this. Birds have their eyes located on the sides of their heads. They have a huge visual range, a panorama if you will, but lack stereopsis because the images from their eyes don't overlap. As a result, they can't use that method for depth perception and are strictly reliant on the other cues I mentioned. They seem to do pretty well for themselves though, except when they fly into buildings.
Do your homework next time. Our individual eyes see strictly 2D images. The world may be 3D, but our senses are limited. Just because something HAS an attribute doesn't mean our eyes can magically detect it, there has to be some mechanism in our eyes that they can use TO detect it.
If you understand that mechanism, you can manipulate it to feed it all sorts of data in the form of illusions. The 3DS and all 3D technology uses EXACTLY the same mechanism that our eyes normally use to process two 2D images into one 3D image. It works in the same way and, to our brains, is indistinguishable from the real thing. Explain specifically why that shouldn't be the case. Also, keep that quote. It should remind you to not make assumptions and do proper research.
"On two occasions, I have been asked [by members of Parliament], 'Pray, Mr. Babbage, if you put into the machine wrong figures, will the right answers come out?' I am not able to rightly apprehend the kind of confusion of ideas that could provoke such a question." ~ Charles Babbage (1791-1871)