
Magic Leap House of Cards – FSD, Waveguides, and Focus Planes - QAPereo
http://www.kguttag.com/2018/01/06/magic-leap-house-of-cards/
======
ghusbands
You're not going to find the technical truth on this blog. Look at the history
of posts; the author clearly believes that Magic Leap is fraudulent at its
core and wants to prove it. Everything Magic Leap does/says is attacked from
that inherently biased position. Any facts or data presented on the blog will
be with that goal in mind, and any facts or data that support the opposite
will be downplayed or omitted.

I don't know whether Magic Leap actually will produce anything of merit, but
this blog won't help anyone find out.

~~~
bhouston
A lot of experienced people in the computer graphics industry doubt Magic Leap
and their claims -- myself included.

It is a fact that what ML started out saying they were going to do is not what
they are currently doing. And what they are currently doing is incredibly
similar now to the Hololens.

> I don't know whether Magic Leap actually will produce anything of merit, but
> this blog won't help anyone find out.

I think the author of this blog post isn't wrong.

~~~
zero_intp
The author of the post is trying to prove the negative, that ML can not
succeed because GP can not reconcile a successful solution from the the
disclosed technologies, or that one does not exist. This may be true, but can
not be proven.

~~~
bhouston
Dealing with ML often feels like dealing with climate change deniers.

But ML has pivoted away from nearly all of their major technology advances at
this point, so they are much more likely to deliver now what is likely to be
an underwhelming product that is little differentiated from Hololens.

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QAPereo
Another post from today, really laying out the math behind hi-res FSD being a
bad joke.

[http://www.kguttag.com/2018/01/06/magic-leap-fiber-
scanning-...](http://www.kguttag.com/2018/01/06/magic-leap-fiber-scanning-
display-fsd-the-big-con-at-the-core/)

Key point...

 _Thus the fiber needs go 10.17 meters X 240 /sec = 2,400 meters/sec. For
reference, the speed of sound is a mere ~343 meters per second (varies with
temp and air density) so the fiber has to average about 7 times the speed of
sound and because it is accelerating and decelerating back to zero at each
end, it has to have a peak velocity of greater than 14 times the speed of
sound!!!!!_

~~~
drcode
I'm definitely a Magic Leap skeptic, but these Karl Guttag posts do not read
like posts from someone who is trying to do an objective analysis of the tech,
they read like posts from someone who has an axe to grind. Often, when I see
posts from very smart and technically savvy people that call things "cons" or
"scams" it's because they have very high personal standards of technology and
are disappointed that others do not share their views.

Frequently in these situations, it turns out that the mass consumer market is
still satisfied with the product, since their expectations of the technology
are more modest than those of a tech expert.

I guess only time will tell whether Magic Leap will end up being a "con" or,
instead, whether they are able to put in place some crude mitigations for
these technical challenges that allows them to still release interesting and
usable technology. In the latter case, the technology would likely still have
flaws that Karl would find wholly unbearable, but may nevertheless allow for
compelling products for ordinary consumers.

~~~
kguttag
Objective is often in the eye of the beholder. I do express opinion, but I try
to back them up with evidence.

The Fiber Scanning Display is in a whole different category. This looks like
pure lying on Magic Leap's part.

In this particular case I have tried to lay out the math that proves that
Fiber Scanning Displays are never going to support high resolution. No amount
of money or time is going to make Fiber Scanning Displays work. I picked this
case because the math was simple to follow and easy to prove that it was not
possible. Yet it has been a key point in Magic Leaps Presentations and patent
applications through to the latest ones printed.

I think it is a very valid point to asked how a company could have been
presenting something that was not possible, why people invested in a company
saying things that were not possible, and why Magic Leap is holding to the
fiction that it might be possible.

It seems to me to be a pretty simple question. Were they lying or did they not
know what they are doing?

There are other areas of optics and image quality where you can argue about
whether the image quality will be "good enough" but Fiber Scanning Displays is
a black and white issue.

~~~
UncleEntity
> Were they lying or did they not know what they are doing?

This (less biased) article[0] seems to suggest your analysis is a bit off.

Isn't there some old saying about how an engineer can mathematically prove a
bumblebee can't fly?

[0][https://gpuofthebrain.com/blog/2016/7/22/how-magic-leap-
will...](https://gpuofthebrain.com/blog/2016/7/22/how-magic-leap-will-work)

~~~
yorwba
That article doesn't really address the issue of the fiber speed except for

"By using a piezoelectric actuator to achieve this scanning, one can maintain
scan rates on the order of 10s of kHz"

10 kHz at a framerate of more than 100 Hz gives you less than 100 vibrations
per frame. If each vibration covers a single row of pixels, you need at least
a dozen fiber displays to produce a high-resolution display. There will likely
be artifacts at the boundaries, but it might be possible to compensate.

After reading this, I think that the technology might be possible, but it
likely won't be as amazing as claimed by Magic Leap's PR.

~~~
kguttag
The GPU of The Brain author seems to be well meaning and nice guy but he don't
not understand optics.

The parallel fiber idea is "optically silly" but it takes some understanding
of light to prove it is impossible too. It is yet another example of trying to
fool people. I did try and explain this before on my blog over a year ago. See
[http://www.kguttag.com/2016/11/20/magic-leap-separating-
magi...](http://www.kguttag.com/2016/11/20/magic-leap-separating-magic-and-
reality/) and scroll down to the Appendix at the bottom.

Basically you have multiple fibers going in a circle each with their center of
origin it becomes impossible to get them to act like a single image for use in
near eye optic.

What the layman would not understand is that this is very different from image
stitching on a projection screen that in part relies on the light being
diffused/randomized by the screen. In the case of near eye optics, there is no
way to get the multiple projector image collimated AND seamlessly put
together.

It is yet another example of a good con has to seem believable.

~~~
UncleEntity
> Basically you have multiple fibers going in a circle each with their center
> of origin it becomes impossible to get them to act like a single image for
> use in near eye optic.

Why would they go in a circle when all they need to do is provide a single
wavelength on a single axis? A single axis movement seems to be enough, no?

> In the case of near eye optics, there is no way to get the multiple
> projector image collimated AND seamlessly put together.

Unless they did something completely crazy and invented a method to do this.
And maybe with this "invention" they built a demo and showed it to a few folks
who were like "hey, this really works, I think I'll write an article about it
and get published in Rolling Stone" or "Dude, take my money, please."

Reminds me of another story (definitely true and not about bumblebees). Henry
Ford wanted a V8 engine block made out of a single casting and _all_ the
engineers said it wasn't possible. So what to do? Turns out throwing a shitton
of money at a secret project lead to the answer and the flathead ford V8
engine was the result.

~~~
yorwba
> Why would they go in a circle when all they need to do is provide a single
> wavelength on a single axis?

Going in a circle (really a trochoid) is actually a pretty smart way to scan a
2D surface with a single light ray, you basically just rotate the vibrating
fiber's plane of vibration around an axis to produce a cone of light. If you
wanted to have only a single axis movement, you'd need many more fibers, one
for each row of pixels.

>> In the case of near eye optics, there is no way to get the multiple
projector image collimated AND seamlessly put together.

> Unless they did something completely crazy and invented a method to do this.

Did you read kguttag's argument on the matter? The reason this doesn't work is
because the optics for collimation depend on the incoming angle of the light,
so it must happen close enough to the light sources that the different light
cones do not overlap. Then the light still expands within the optics before it
gets straightened out, so there needs to be some gap for tolerance. So either
they end up with some stray light rays that go into undesirable directions, or
there is a gap at the border between the different regions.

Now maybe they showed a demo of this with visible artifacts to people and they
were still blown away. Most likely they also told them that there was still
room for improvement, while leaving open where exactly the fundamental limits
are. Maybe they will release the imperfect version of their product than can
actually be built, and people will still love it despite not living up to the
marketing.

The problem is not that Magic Leap's ideas are completely useless or
impossible to implement, just that they are significantly overhyping the
expected capabilities of the finished product.

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Steeeve
I thought Magic Leap had already waived the white flag and decided to become
yet another goggle vendor.

~~~
bhouston
They have practically done that, none of their unique technology works, but
not everyone is aware that this is what has happened.

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deepnotderp
Also Moore's Law in this context doesn't even seem to make sense, the "Law"
deals in transistors, not optical technologies.

~~~
kguttag
Sorry if that was not clear, but what you said was the point I was trying to
make.

People today are all the time waving their hands and invoking "Moore's Law"
and saying "Steve Job did this" and applying it to everything (I see it all
the time in AR and Optics) and therefore anything is possible.

~~~
throwawaybbqed
You mentioned CES prep .. are you presenting or at a booth? Or just packing?
:) I went for the first time last year and didn't get to see to much stuff in
optics (the big wow for me was seeing Kopin modules). Would love to get your
thoughts on what is worth checking out at the show this year.

~~~
kguttag
I'm there as "press" and a consultant. I have been juggling my calendar (I'm
almost fully booked from before 9AM past 6PM the first 3 days) and getting
back to people I am meeting with. In-between I am studying up (prepping) on
the companies I am going to be meeting with.

I can't say who I am going to see as a lot of it is private. I will be
spending a LOT of time in the Main Convention center South Hall with the AR
and VR companies. The special section for AR and VR has moved from the back of
South Hall to near the front this year. Then you have to look for the more
established companies that booths elsewhere.

The CES tools for finding booths and vendors have improved dramatically form
where they were a few years back. You can search based on what you are trying
to find. They also have a smartphone ap that comes in handy at the show.

~~~
throwawaybbqed
Thank you for the info. I noticed that AR/VR seem to have a bigger presence
this year .. very excited for that! I'm an early-career professional scientist
(on the SW side) .. I must say, I learned a lot about the capabilities of
current hardware by talking to engineers at CES. I'm reading up on LCOS,
waveguides, combiners, etc. so I can have meaningful conversations! I am a big
believer in wearables (still have my Google Glasses!) ... it would be a dream
if we had high quality wearable AR in the market. The main barrier to
experimentation is that it is pretty hard to source and integrate the
necessary optical systems. I read your older articles on LCOS with combiners.
Are there specific modules you'd suggest a "hacker" to try out? (i.e. hobby-
level resources as opposed to corporate-level).

------
shadowmint
> But everything I can see as an engineer says that Magic Leap’s display
> hardware is not going to have very good image quality and it is going to be
> expensive to make.

So what? What are we supposed to take away from this?

Even if true, its clearly not stopping them, and its not clear if that will or
will not make a successful consumer device.

If its rubbish, a few of people will lose a lot of money and we’ll all move on
with our lives a bit disappointed, but otherwise not really caring.

The sooner they ship whatever it actually is, the better.

This kind of idle speculation is just gossip.

