Re: why 3d is no longer popular - article


Several times I had mentioned that I recommended reading McKay's book first
I did not notice this recommendation, or did not linked it to this list.
If it is your website, maybe you could write it on the page or change the order of the books.
which helps understanding many of the words used in the other books.
It was more a problem of understanding English than stereoscopic terms in my case. I will read this one too though.

You are mixing metrics.  IPD is interpupillary distance, which is the distance apart of the eye pupils, NOT the on-screen disparity.
I used multiples of IPD as a distance unit because it is easier to reason this way thanks to the invariance (the same trick used in the N metric of the book by the way), but you can convert it to millimeters or inches if you prefer. (e.g. -2×IPD means -130mm with standard IPD of 65mm)

Any on-screen specification is meaningless without also specifying the viewing distance to the screen.
In absolute yes, but in this case it can be omitted because the depth behind and before the screen grow proportionally with the distance of the observer to the screen (so the smaller one stays the smaller one at all viewing distances). If you cannot reason with the general case, place an object with 50mm disparity on the screen (which does not diverge even for children), choose a distance for the spectator, choose his IPD, choose a position for your object in front of the screen (that can be seen) and compute the apparent position of the two objects relative to the screen. You will see that the object in front is closer to the screen than the object with 50mm on-screen disparity (in absolute value).

What are you referring to as "pop"?
I was using this term as "the effect that some parts of the image appear in front of the medium on which their stereoscopic image is displayed".
many times more than positive parallax behind the screen, which is extremely limited before you exceed parallel vision
I do not know if you talk about the parallax on the screen or about the space behind the screen.
The range of the parallax (on screen) is smaller and more limited in the positive direction, but what matters in my opinion is the space apparent behind the screen that it produces which is bigger. Again, use some real numbers to see it if you need. If you limit the size displayed behind the screen so that the maximum disparity is 50mm on the screen, you still have more space behind than in front of the screen.

I suggest that you read some of the other books as well, and learn something about the basics of not only stereoscopic composition, but all of stereoscopy as well.
I will definitely continue to learn, but on the topic of depth budget relative to the screen, I am confident now. Of course if you can give an example where it does not work, I will reconsider my position.

No, I disagree. When a train stops, you have still your binocular vision, so that you see what is close and what is farther.
If you think about the distant mountains, they are at the infinity when the train is stopped so the binocular vision does not help, but we sense their depth thanks to the parallax induced by the movement of the train.

"wiggle stereo" is clearly an example of showing motion parallax
Sure. The two images are taken from different viewpoints so there is parallax visible in the animation.

seeing the parallax presented vertically really registered with her
Very interesting. I know someone who is stereo-blind too, I will try to remember about this the next time we meet.


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