Hello Mr. Poissant,

As you suggested, I’ve created my own thread and i have purchased the newest version of Animation Master, which is on it's way. But in the mean time i'd like to know if the new Animation master has a plug-in or a property for diffraction and the creation of iridescent materials. And if so, will this effect radiosity in the render? as it should.

Physics Lesson

Diffraction:
Surface roughness causes diffuse reflection. When the roughness has a regularly repeating pattern, with pattern separation on the same order of magnitude as the wavelength of incident light, the resulting phenomena is diffraction. The incident light is broken up into two components: the specular component and the diffracted component. The specular component obeys the law of reflection, and will have the same spectral composition as that of incident light. The diffracted spectrum will be broken up into a rainbow, with the light of shortest wavelength located closest to the specular component. The degree of separation depend on the wavelength and the pattern size.

There are no plugins that does spectrum diffractions for A:M. A diffraction shader, to work properly would need full spectrum color specifications for the surface. Not only RGB. And would require full BRDF specifications too.

This said, it should be possible, for a clever shader programmer, ti write a plugin that would fake that phenomena.

Do you know if A:M is working on any current work projects or moudule for diffraction? cause... it's a big part of the natural world... things like diomonds are able to slip light and shoot if off into hundreds of dirrections.

You can do caustics with Photon mapping.

lol Take a closer look good sir. Rainbow diffraction in the caustic.

OK, let me spell it:

a. You can do caustics with Photon Mapping.
b. you can use an array of lights in a scene.
c. You can have lights of different colors.
d. You can arrange your lights colors so that they all add up to white.

So

If a and b and c and d then ...

Do I need to add the bars on the t's?

3D is all about figuring ways to fake reality. Others have succesfully done that in the past. I'm sure you can too.

You are giving a physics lesson on diffraction due to surface roughness and regularly repeating patterns, but you realize your photo doesn't have much to do with that, don't you

Isn't the rainbow out of the diamonds a product of refraction, not diffraction? If diffraction is about surface roughness, that really isn't what diamonds are about. Diamonds are about refraction.


Anyway, while not exactly the same thing, Marcel Bricman has demonstrated a way to get a related rainbow effect. It might get you started.

http://www.kci-group.com/z/gradientz-tut-disp.htm


embarrassing faux pas #2:

Although what you describe doesn't have much to do with diffraction either, ZPiDER has managed to fake this effect pretty convincingly. Using the same idea together with caustics should give you what you want.

Will it slow down the different light frequencies as it passes through refracted/reflected points if i do this? And that's quite a lot of lights to make all the colors into white light...



Diffraction is the bending of light into a field of all it's frequencies after it has hit some obstruction; which could be clouds, fog, rain, oil, the atmosphere, diamond edges, etc. Refraction is the bending of light on incedence to normal angle absorbtion through transparent objects. When difraction and refraction are combined they create rainbows and such... like in the diagram below.



You seem to have quikly forgoten your physics classes Mr. Avver, but to achieve diffraction you have to have a material of repeating patterns, such as equally spaced water molecules in low atmosphere to create a perfect rainbow... i think you would be hard pressed to see a rainbow if light was skattered "all willy nilly" among some loose, unassosiated, group of molecules that had no regular repeating pattern.

But, what ever. We're all here to have fun making stuff on animation master. By the way, robcat2075, i was unable to open that link you gave me. Is there another that you might have?

Off the topic, anyone know if there's a car contest anytime soon, or where i should post something like this?

Are you absolutely sure about that? Have you considered the possibility that you havn't understood what you remember so well from your physics classes?

So if what you say is true, what mechanism makes the water molecules in low atmosphere form this perfect repeating pattern?

Of course you will not see a rainbow if light was scattered randomly, but if - hypothetically - the rain drops were spheres and if there was one prominent plane wave light source, wouldn't there be some position where you would experience a rainbow?

Or do you mean that refraction is incapable of producing rainbows on its own?

Sorry for the sarcasm, but a little bit of modesty would suit you better

The link works. Just cut and past it...

I dont know how this got out of hand... but diffraction is a part of refraction... it's why we have blue skys... and orange sunsets. all refraction yeilds a percentage of diffraction... it's everywhere, all the time... but diffraction does not neccisarily demand refraction to make a rainbow effect... it could be from a peaked mirror... or a hillside: in the case of radio waves. And a water drop, in itself, is a repeating pattern... I was just wonderin if there was inridecent materials on A:M... how did this get out of hand.

That link is amazing... it looks almost real.

diffraction and refraction are distinct from each other, although in certain circumstances they can produce things that have some visual similarity. Neither one is a subset of the other.

refraction requires that light travel through a solid. The diffraction you reference above is light bouncing off a solid. two very different things.

quotes from the wikipedia

Maybe it was when you wrote



But this is the Internet and you couldn't possibly know that this "Mr. Avver [sic]" just maybe holds a Master of Science degree in Physics so just keep on make something stunning with A:M and you will be forgiven

BTW, your car is really cool! You are forgiven!

test:
volumetric laser -- (more like "small angle kelig," lol) -- radiosity/refraction/diffraction
c/v: 2.419

is there anyway to recreate a laser in A:M? This test created a falloff of the volumetric prior to it expanding out.

The thing is, you can't get real lighting in animation master based on the limitations of the lighting source. When a light is turned on in a scene, it is instantly everywhere that is in the range of the light. It doesn't take into consideration the speed of light. I'm mean that it would (in reality) it would take around 4.28 years for light from the earth to get to Proxima Centauri. So what you would have to do is make a plug-in like Yves said to, which alters the way refraction is calculated and displayed on rendering.

Oh, and Robocat, don't mean to be rude or anything, he wasn't saying that diffraction is light bouncing off of the solid. Light goes through a solid when it is diffracted. The only thing is, you can see individual colors of the light. That's because blue light travles at a different speed than red light. That's why when things move away you get a redshift, and when things move tawards you you get a blueshift.

PS: Yes the car is pretty nice looking, though the scene is a little dark. (Doesn't have radiosity yet, which is the name of this thred, which makes me wonder why difraction is in here).

Not in this universe

I think you are mixing things up a bit.

No not generally.

This I don't understand. When do you se individual colors? As I see it, you get a color spectrum from refraction or interference (e.g. diffraction) you don't have to combine them.

This is called dispersion and is the phenomenon behind refraction, but has nothing to do with diffraction.

This is because of the doppler effect and has nothing to do with neither diffraction, refraction, dispersion nor interference.

hmm.... Don't I feel stupid. I must go on a quest for knowledge on diffraction... even though Hash doesn't support it.

I smell troll.

To be fair, jr. high school student != troll.

Are you calling me a troll? Hey now... that's not very nice at all there buddy.

Psst! Dan! That Martin guy, up there? His last name is Hash. He created the software you just bought.

But I'm sure he'll be your buddy, too.

He designed it? Cool, maybe he'll add diffraction to the new versions of the software. But beware, that crazy diffraction math will get'cha. I mean, I was in calculus, and it still looked crazy. I mean l look at it.

Crazy Math

I don't even know what the lambda stands for in the equations.

I mean... Martin Hash is god of the universe. All hail Lord Hash! and give thanks for him creating an affordable program for all us money disinclined 3d amatures and proffessionals alike.

The lambda stands for wavelength. but an even better question is, "what the heck is that symbol that looks like a greek colum krater in that wikepedia link?" good grief.

I think it stads for wave length, though maybe their talking about the lambda. Allround, just crazy. They don't even tell you how to calculate it over a time interval or anything. The just expect you to know everything about Huygens' principle. Silly scientists, tricks are for kids...

"greek column krater"

I think you refer to the greek letter Ψ,(Psi).

In this case it seems to stand for a general complex valued wave funktion.

to answer the original post, you can always fake the diffraction with a material. I did this tut back in version 6.5, but it still is valid for v12.

http://www.babbagepatch.com/cd/

Charles Babbage

WOW! That effect looks amazing! I realy have to try this now. That tutorial is very helpful.

Thanks Mr. Babbage

you people talking about different things and naming the right things wrong.

dispersion is something else than diffraction, both produce a similar result.

i doubt, that its possible with an a:m plugin or, for that matter - with any linear solution - to code realistic diffration or dispersion.

i believe, that the subframe - multipass - solution i've presented earlier is the best you can get and you can get it with a:m. it behaves cubic though, meaning: higher effect quality will severely influence render time.

Those are pretty neat tricks. But since this is the radiosity thread, I've got to ask. Does the material change how radiosity is rendered? I mean, does it make the reflected area change in the color that the iridescent is?

multipass works like this:

a:m just renders "sub-frame steps" and blends them together.

this means each step gets its own lighting, i havent done much with radiosity yet, but i'll assume it also gets recalculated for each step. (yves?)
this means the trick SHOULD also work for caustics.

dont forget to increase the intensity of involved lights, as only one Nth (N being the multipasses) of the light intensity will show.

If it does it frame by frame that would be awsome! Though I can see situations where rendering radiosity once and using that for a room that doesn't change a lot over a camera change would be a little quicker. So what we sould do is all pitch in and buy ourselves a Cray X1E. Liquid Cools of course. Then we could network our projects into the cray for rendering, and *BAM* instant animation.

Hey!

Yes