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What Is 3D? - The Less Technical Version
What Is 3D? - The More Technical Version
Old 3D versus New 3D

What is 3D?  It’s a good question with more than one answer.  However, the only answer we’re concerned with here is “What is 3D to humans?”   To illustrate what I mean, let’s say that “3D to science” is “three dimensions.”  Nothing more.  Nothing less.  Our universe has three spatial dimensions for matter and energy to traverse.  However, this is not what 3D is to humans.  For humans, it is the ‘perception’ of three spatial dimensions-of three perpendicular directions that each allow us to distinguish objects by size and position.  This distinguishment between ‘science 3D’ and ‘perceived 3D’ is very important, because it is the basis for all modern 3D technology.

Humans have a variety of internal and external senses.  Some of them, like sight and hearing, have multiple, distinct, directionally specific input points (two ears, two eyes).  Others are localized with relatively passive inputs (taste, smell, balance).  Still others are exceedingly complex and have innumerable local variations (touch, pain, relative body position).  The concept of ‘perceived 3D’ applies to all of them because the inputs they experience vary with spatial position and surroundings.  However, the ‘perception of 3D’ applies to some of them more than others.

Observing the real world is a matter of all of your senses coordinating to tell you the same thing.  But what if we want to reproduce the real world?  Or even create the illusion of a complete imaginary world?  To truly do this, we would have to recreate every sensory experience of the original world in tandem.  This is a monumental task.  So monumental that attempting to do so would bankrupt any normal company.  The solution?  Real companies have instead opted to create the closest representation of total sensory input that their engineers can design.  This has led to two ‘rules of real world approximation’: to “recreate the most potent senses with the greatest variety of inputs” and to “recreate inputs that are the easiest to mimic with respect to cost and time.”

If the majority of humans did not have a sense of vision, I’m sure you can imagine how elaborate our sound systems would be.  If humans also had no sense of hearing, then false, tactile 3D arrangements would probably be commonplace.  So even though you may think of 3D TVs as an attempt to reproduce imagery, they're actually the cheapest and most effective way to reproduce a complete 3D environment.  That is, television follows the rules above.  The sense of vision has the strongest input with the greatest variety and ease of reproduction; and the sense of sound is comparable.  Televisions don’t reproduce the other senses because they don’t fit in with the rules.  Reproducing taste, smell, and touch has historically proven to be difficult, expensive, inconvenient, or ineffective.

But why are sight and sound easy to recreate?  Because they rely on distant sources.  To mimic the sense of touch, you actually need to have something at the correct location on the body.  You can’t send ‘touch signals’ from a single source (at least there is no modern technology that does this).  The same goes for taste and smell, which not only require proximity, but specific chemicals to be present as well.

3D technology is primarily focused only on the senses of sight and sound, because emulators of other senses are uncommon.  Coincidentally, these two senses also have two distinct, directional inputs (eyes and ears), which is where the concept of “New 3D” really comes in to play.  If you consider each sense as a whole, existing “2D” televisions and mono speakers already attempt to recreate 3D.  It may seem illogical when you consider TV as flat and a mono speaker as a single point, but when you dissect the images and sounds, their 3D nature becomes clear.

Objects on a television screen appear to change sizes and shape as they move, just like in real life.  Sounds from a single speaker grow louder or quieter as their sources move, just like in real life.  Just because both of your eyes and ears don’t hear the correct things independently, doesn’t mean that the simulation of 3D isn’t already present.  Even the most basic of cartoons attempts to simulate perspective.  This “Old 3D” is everywhere, you just think of it as 2D right now.

But you’re here to learn more about the New 3D, not the Old 3D that has been around since the first television and speaker.  Well, the difference is actually pretty simple.  Old 3D “recreates 3D for a whole sense” and New 3D “recreates 3D for each input points of each sense”.  You may already know what I mean for sight and sound, so I will start with “touch” as an example to set the stage.

Haptic feedback is the Old 3D version of touch.  It uses a device that shakes (usually a controller or seat) to simulate physical contact.  It’s Old 3D because it can only simulate more or less touch through the degree of shaking, not different forms of touch and in different locations.  A New 3D setup for touch would have to address every part of the body and would likely be extremely elaborate even in its simplest form (hence the reason why it doesn’t exist commercially).  Now, through the example of touch, you also know what I mean for sight and sound.  Old 3D images and sounds create the same inputs for both eyes and ears, New 3D images and sounds create different inputs for each eye and ear.

This may all seem like a uselessly elaborate way of answering “What is 3D?”  But consider how a quick answer would have been “3D means a different image for each eye,” versus what you now know, that 3D is “the attempt to coordinate as many senses as possible to simulate real life,” and that it can further be broken down into Old 3D and New 3D depending on whether the simulation affects an entire sense or each input point of each sense.  This definition allows you to see that modern television is already 3D, but that many more advancements are still possible to make it more 3D.  Those modern advancements are the focus of 3DGuide.org.

Note: I should warn you that every use of the term “3D” from this article was only referring to three “spatial dimensions.”  In my book, “How to Make a Holodeck,” 3D is not so concrete because it uses time as a possible dimension.  I actually prefer the term 4D for most instances where people use 3D (i.e. where there is something changing with time), but I still use 3D as I did here for ease of understanding.

3D stands for three dimensions.  But it’s actually much more than that.  It’s the experience of living in, feeling, seeing, hearing, and touching everything around you.  It’s the experience that drives creators to make televisions, video games, and even books.  In this sense, 3D is an attempt to recreate an experience, or more specifically, to recreate the ‘perception’ of that experience.

We have many senses.  Some-like taste-are local and ask “what’s this?”  Others-like sight-are distant and ask “what’s that?”  Ideally, if we were to fully recreate the experience of living in the real world, all of those sensations would work together in harmony, just like they are doing for you right now.  Unfortunately, some of those senses are harder and more expensive to copy.  This means that we have to pick and choose the senses that give will give us the closest experience to real life, but won’t put a hole in our pockets in doing so.

Inventors, designers, and engineers have historically determined that the best senses to reproduce are sight and sound.  They may not have said so specifically, but it’s implied by the TVs and speakers that surround us everywhere we go.  Sight turned out to be a good candidate for imitation because it’s one of the strongest senses and it only faces one direction.  Sound is good because it’s the simplest sense to duplicate and our ears can hear that duplication from just about any direction (we can hear speakers no matter where they are around us).  Sight and sound are also good because they can be mimicked from a distance.  You’ll know what I mean the next time someone asks you to taste their slice of pizza over the phone.

So copying the real word boils down to copying sight and sound because copying any more then that costs too much time, money, and effort.  Well, these two senses have an interesting trait in common.  They both have two places where they can receive sensations-that is, two eyes and two ears.  This means that there are two different things you see and hear for every situation.  Even if they are almost exactly the same, they rarely are exactly the same.

Without even considering that sight and sound can reach two different places, TVs still try to duplicate 3D.  Even if you only had one speaker on your TV (“mono” sound), every object you see on the screen would still look and sound like it’s really in 3D.  When a on-screen character walks away, they get smaller and their voice gets quieter.  Our eyes and ears sense that something is amiss because they both see and hear the same things (which isn’t what real life is like), but they still think of the objects and sounds as having some sort of depth.  To test this, look at two people on a TV screen and answer, “Which person is further away.”  You will be able to answer immediately that one person appears to be further away even though you know deep down that they are both at the distance of the screen.

Still, each of your eyes and hears know when they are being misled.  Your brain will take two identical images and sounds and tell you ‘where it guesses things are located’, but if it has two different images and sounds it can go a step further and tell you ‘where things really are located’.  The difference is not whether you see or hear 3D, but the degree to which you see and hear 3D.  So the real answer to “What is 3D?” is that it’s “the best approximation of the real world that we can make.”  3DTVGuide.org is focused on the modern technology that makes that approximation better.


Change is Silver

Author of “How to Make a Holodeck” (5Deck.com)
~A humorous book that describes a new type of 3D and 4D display technology.
Creator of Unili arT (UniliarT.com)
~Original designs on “car hood stickers”, bumper stickers, and other products.
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