[Bored chemist]

There is no computer program out there that is going to know what to do if you tell it to draw a laser beam through milk in slow motion.

Nobody said there would.
You made that bit up.

Would you like to quote the bit you think says you are right?

[Bored chemist]

Let's look at what they actually say.
"we created a virtual camera that was fast enough"
"we could capture light as it spreads through the virtual scene"
" 2D light transport simulator "
"Monte Carlo raytracing"
"we assign our virtual camera"
"To keep track of time along light paths, I will be using a slightly modified geometric optics model"
"on top of our existing 2D renderer with only a few lines of code."
"we use a conventional 2D renderer"
"We annotate each vertex on these light paths with a timestamp"
"store these in memory"
"we iterate over all segments"
"splat the line segment to the screen"
"we could do it in a vertex shader"

OK, all of those show that the article is talking about computer graphic simulation, not anything real.

But the most interesting line is "Note the strong color separation in the first video: Because the index of refraction depends on the wavelength, different wavelengths travel at different speeds through the glass and begin to separate after the first refraction."
Because that's what explains the fact that the image isn't circular.
One side has a higher refractive index, so the light spreads less far.

[trevorjohnson32 (OP)]

Nobody said there would.
You made that bit up.

Yes you did you said that's a computer animation of a laser beam going through milk, for no real reason either.

[Bored chemist]

Nobody said there would.
You made that bit up.

Yes you did you said that's a computer animation of a laser beam going through milk, for no real reason either.

You just saw my reasons for saying it's a computer generated animation but...
OK, if it's a film of a real laser hitting real milk, how come the milk starts off as a vertical line?
In the real universe it would form a a chain of drops and fall down.

[trevorjohnson32 (OP)]

Let's look at what they actually say.
"we created a virtual camera that was fast enough"
"we could capture light as it spreads through the virtual scene"
" 2D light transport simulator "
"Monte Carlo raytracing"
"we assign our virtual camera"
"To keep track of time along light paths, I will be using a slightly modified geometric optics model"
"on top of our existing 2D renderer with only a few lines of code."
"we use a conventional 2D renderer"
"We annotate each vertex on these light paths with a timestamp"
"store these in memory"
"we iterate over all segments"
"splat the line segment to the screen"
"we could do it in a vertex shader"

OK, all of those show that the article is talking about computer graphic simulation, not anything real.

But the most interesting line is "Note the strong color separation in the first video: Because the index of refraction depends on the wavelength, different wavelengths travel at different speeds through the glass and begin to separate after the first refraction."
Because that's what explains the fact that the image isn't circular.
One side has a higher refractive index, so the light spreads less far.

Ok I bet you know what every thing you just quoted means from your cube drawing days. It's a real video of light through a virtual scene. Or I guess for all you know (which seems to be everything) there using a camera and its shudder to film the video they made on the computer.

"In Monte Carlo raytracing, Femto Photography is very simple to set up. First, we assign our virtual camera a time interval [t0, t1] during which the shutter is open. Rather than rendering all light that reaches the camera, we now only allow light that took between t0 and t1 seconds to reach the sensor."

sounds like they're filming light with a camera to me. Or maybe like you said they're making a film out of drawrings they made.

[trevorjohnson32 (OP)]

OK, if it's a film of a real laser hitting real milk, how come the milk starts off as a vertical line?
In the real universe it would form a a chain of drops and fall down.

What?

[Bored chemist]

filming light with a camera to me.

And it sounds like they are doing monte carlo ray tracing to me- because that's what they say they are doing.
And ray tracing is a way to make computer generated images.
https://en.wikipedia.org/wiki/Path_tracing

If you had real pictures, you wouldn't need ray tracing.

Do you realise that virtual cameras have virtual shutters?

What's really remarkable is that you quote this "we assign our virtual camera" as evidence that the camera is not virtual, but real.
Do you have to get up early to practice that sort of broken logic?

Ok I bet you know what every thing you just quoted means from your cube drawing days.

No, I learned it more recently. Most of those techniques weren't widely used back then- not enough computing power.

But they are used today.
And they are used in that animation- which is why the accompanying text says they are.

[Bored chemist]

There are, of course, other things that make it clear that the video isn't really light entering milk.
For a start, you don't get a vertical line with milk on one side and air on the other, because milk is liquid.

Also, on one side the light goes through air, and on the other side, through milk.
But the scattering by air is tiny compared to the scattering by milk.
The light from the milk should be vastly brighter than that from the air.
It's not.

[trevorjohnson32 (OP)]

And it sounds like they are doing monte carlo ray tracing to me- because that's what they say they are doing.
And ray tracing is a way to make computer generated images.
https://en.wikipedia.org/wiki/Path_tracing

Your article says "When combined with physically accurate models of surfaces, accurate models of real light sources (light bulbs), and optically correct cameras, path tracing can produce still images that are indistinguishable from photographs."
So though its partially animated its based on reality.

[trevorjohnson32 (OP)]

But the most interesting line is "Note the strong color separation in the first video: Because the index of refraction depends on the wavelength, different wavelengths travel at different speeds through the glass and begin to separate after the first refraction."
Because that's what explains the fact that the image isn't circular.
One side has a higher refractive index, so the light spreads less far.

It says light at different wavelengths travel at different speeds, why would light of the same wavelength be bent by diffraction more in one direction then the other?

[Bored chemist]

And it sounds like they are doing monte carlo ray tracing to me- because that's what they say they are doing.
And ray tracing is a way to make computer generated images.
https://en.wikipedia.org/wiki/Path_tracing

Your article says "When combined with physically accurate models of surfaces, accurate models of real light sources (light bulbs), and optically correct cameras, path tracing can produce still images that are indistinguishable from photographs."
So though its partially animated its based on reality.

The models are, indeed, based in reality- stuff like Snell's law and the reflection law. Do you understand what they mean by "model"?
They mean a set of mathematical equations. They do not mean glue and cardboard.
That is not the same as saying they are based on a film of real light or that they use a real physical camera.
Not least, because as I explained much earlier, they can't actually take trillion frame per second video.

So the video you posted is, whether you like it or not, a computer animation.

[Bored chemist]

But the most interesting line is "Note the strong color separation in the first video: Because the index of refraction depends on the wavelength, different wavelengths travel at different speeds through the glass and begin to separate after the first refraction."
Because that's what explains the fact that the image isn't circular.
One side has a higher refractive index, so the light spreads less far.

It says light at different wavelengths travel at different speeds, why would light of the same wavelength be bent by diffraction more in one direction then the other?

Nobody mentioned diffraction here. Did you mean refraction?

If that question is related to me saying "

One side has a higher refractive index, so the light spreads less far.

then the answer is simple, there is milk on one side, and air on the other.

[trevorjohnson32 (OP)]

So the video you posted is, whether you like it or not, a computer animation.

Well of course what you really mean is the video is fake to satisfy your need to be unconditionally right. You know its a little insulting to listen to a pompous POS like you about a topic you only learned about as I pointed it out to you. Why don't you step back.

[Bored chemist]

ou only learned about as I pointed it out to you.

LOL
As I pointed it out, I knew it ages ago.
You, on the other had, seem to not understand it yet.

Well of course what you really mean is the video is fake to satisfy your need to be unconditionally right.

No, I mean it's a computer animation, because it can't be anything else.

Have you found out how to read a clock yet?

[Bored chemist]

You know its a little insulting to listen to a pompous POS like you

That's interesting.
It is more than a little insulting to be called a pompous  POS by someone who has pretty much failed to get anything right yet.

Why don't you step back.

Because I'm right (and you know it).

[Kryptid]

what other experiments?

The Michelson-Morley experiments, for one: https://en.wikipedia.org/wiki/Michelson%E2%80%93Morley_experiment

This much more recent one as well: http://www.exphy.uni-duesseldorf.de/Publikationen/2009/Eisele%20et%20al%20Laboratory%20Test%20of%20the%20Isotropy%20of%20Light%20Propagation%20at%20the%2010-17%20Level%202009.pdf

[Colin2B]

I think most of us are having difficulty reconciling these 2 statements:

I took Computer drafting for four semesters.

Do you even understand how computer animation works? You would either need a picture of animation in question or have to make a hand drawing of it.

I’ve worked with a number of computer animators and video companies to make illustrative videos to explain new concepts. None of them ever use a picture or hand drawing as input to an animation, they either enter formulae or use a GUI to define coordinates and object size, add rendering etc.
This is an animation not an overlay to a real film, and the author is very clear about that, all the terms he uses are computer graphics ones. He even says “In Monte Carlo raytracing, Femto Photography is very simple to set up. First, we assign our virtual camera ......”.

So though its partially animated its based on reality.

It is completely animated.
Not necessarily based on reality. The problem with all simulations is that the accuracy of outcome depends completely on the accuracy of the inputs and of the assumptions built into the computer code. There are a couple of examples in this part of the forum that illustrate this point.

[Bored chemist]

I think most of us are having difficulty reconciling these 2 statements:

I took Computer drafting for four semesters.

Do you even understand how computer animation works? You would either need a picture of animation in question or have to make a hand drawing of it.

No problem at all.
He took the class, but didn't understand it.

But the daft thing is that, even if some of it was real film footage, the bit that matters to his argument can't be real.
It's like saying that Star Wars contains some live acting, so the Millennium Falcon must be real.

[trevorjohnson32 (OP)]

Colin, Kryptid, and Bored Chemist, You guys provide zero useful information the two years I've been on here and you expect me to believe you on whether this a fake or not? ITS OFFENSIVE!!

[trevorjohnson32 (OP)]

Nobody mentioned diffraction here. Did you mean refraction?

So refraction makes the image an imperfect circle. But wait, The light is a different length from center to top and from center to bottom in the same medium. Could it be? The laws of nature defy the laws of bored chemist? pouring his ego down my throat like a baby birds mother vomiting down its chicks throat? That's kind of what your writing on the page looks like Bored chemist, a bunch of sh1t.