That Fundamental AE Alpha flaw creeps up AGAIN... argh!

[Navarro Parker]

Why don't you just render to a codec that supports full 32-bit RGBA channels using straight alphas?

[Zap Andersson]

I ran into this today AGAIN. AE and Alpha just doesnt work right.

I have two files rendered out of 3D Studio max. One .AVI which is the RGB data, one .AVI which is the Alpha. The RGB data is already premultiplied as is proper, but AE has no way to use this properly.

Using the alpha as "Track Matte" doesnt work, you get dark fringe edges due to it AGAIN multiplying the already premultiplied RGB data with Alpha. I've tried "Set Channel" and "Set Matte" and god knows what else..... but I can't get it to work.

Can someone please tell me how on earth you do this?

It's as if I have the RGB data and the Alpha data of a premultiplied TGA file, only in SEPARATE FILES and I simply want to do the simple simple simple excercise of applying the RGB from one and ALPHA from the other. Can't be done.

/Z

[-stev=o]

zap,
just out of curiousity, have you tried merging your files in an editing app (whichever you use) to see if the merge works as you want it there? I know you want to hear a way to do it in Ć, but if you don't want to re-render, and just to eliminate the possibilities, maybe give it a go, just as a test? and as far as what's fundamentally right or wrong, i dunno, and i really don't care too much, as long as people can see their projects come to life. when it comes down to the math, maybe you are right. for example, other apps let you seperate out the alpha and work on it independantly, and hopefully Ć will integrate this option with the next iteration. as you know, there are workarounds, but i'm afraid you're not looking for a workaround, but immediate satisfaction. If that's the case, i hear ya. after all, isn't that what computers are supposed to help us acheive? anywho, if a workaround works, work with it, right?
;p

-stev=o

[-stev=o]

heya zap,
I know you've already tried this, but, have you made sure your imported footage is interperted correctly? short of that, and what you've said you've already tried, i'm outta ideas.
hope you get it working, cause i know we're all looking forward to the next zap-flick!

-stev=o

[Zap Andersson]

Why don't you just render to a codec that supports full 32-bit RGBA channels
using straight alphas?

I have my reasons. Besides, straight alpha are the spawn of the devil. And besides again, it's beside the point. Sure there is "another way" to get the data out of my 3D program. But I have the data. The data is proper. I simply cannot get AE to interpret it correctly.

You can't set alpha interpretation options for a clip that doesn't have alpha. As soon as you set alpha, AE destroys your RGB channels by yet-again-multiplying them with alpha, in spite of my incessant trying to stop it from doing it.

I dunno how many times I have to say that AE's alpha handling is fundamentally flawed before it sinks in on this BB :) :) *grin giggle*

Just tell me how to do it. Anyone? PLEASE!

/Z

[Zap Andersson]

I can merge it properly with the old "hand made alpha compositing" to do it with two layers, first the alpha layer, inverteded, in "multiply" mode, and on top of this the "rgb" layer in "add" mode.

This yeilds the correct composit, so it is "possible" and the data is "right". Yet doing it that way is useless because I want to treat it as one unit, be able to blur, mask, etc. it. Can't do that with two layers.

All I want is to get this into one layer. And it's no fancy compositing, it's just plain old normal stuff. It's just a heavily motion blurred obeject and the black fringing in the blurred area is readily apparent.

With the workaround, it works correctly. I just repeatedly pray for AE to get this simple, trivial, 1985-ish technology thing *right*.

/Z

[Zap Andersson]

Hey, there was a thread about doing back-to-the-future effects too :)

/Z

[Rick Gerard]

The fundamental flaw that I see in your procedure is trying to do everything in a single layer with a single click. Post a link to a frame of your footage/bg/comp problem, not jpgs with no alphas, but the actual footage you’re using, and I'll give you a multi layer solution with complete control over every part of the image. I can't give you a way to control information inside and outside of the alpha channel and maintain control of the pixels on each side of the alpha and in the gray area between (your black fringe) using a single layer or a single plug-in. AE-Photoshop-Combustion-Commotion-Flame-and the Sony switcher in the HD room at Victory Studios in LA all handle alphas the same. White in the alpha means pixels in the other channels are used 100%, black means the pixels are not used, somewhere between black and white they are used in proportion to the value in the alpha channel. (Some apps default to the opposite behavior (black used - white blocked) I don’t see the flaw. I’ve tried, but I can’t see it. I do see that there is a problem with AE’s render pipeline when you choose Luminescent premultiply and want to pre-comp and/or mask the layer. It’s similar to the render pipeline problem with the text plug-ins. I wouldn’t be surprised to see it fixed.

Using multiple copies of the alpha channel footage, or routing a single instance through different busses of a switcher or different levels of a plug-in, you can manipulate the pixel values in any area covered by any alpha value using different equations. Even the shadow on the weather map from the forecasters arm on the evening news comes from splitting off alpha channel information derived from the keyer into multiple copies that are mixed internally to produce a believable shadow. Using one instance of the footage it’s impossible to add the rgb values over black, screen the values between black and white, and use the values over white normally. A good programmer could write a plug in with 3 or more selectable value ranges and apply different operators or transfer modes to those ranges so you’d have only a single copy of your footage in the comp and a single plug-in applied. This would definitely clean up the timeline and probably speed up workflow. But it would still be using multiple copies of the footage internally, the same way a studio switcher does, to achieve the control needed for a seamless composite.

Every time I've seen the black fringe problem you describe it's been an error in interpretation of the footage, or an error in rendering settings for the alpha channel in the first place that causes the problem.

[-stev=o]

heya zap,
heehee....maybe something happened when they released "backtothefuture" in the 80's that messed with the space-time continuum. now if only dan ebberts could finish that quantum particlization/de(re) moleculariztion gizmo....we COULD possibly go back and rewrite the history of compositing with Æ!
on a side note, did you happen to see one of the other threads on this site where effects were ONLY taking place on an alpha and not the RGB? wacky, right? anywho, probably unrelated, but it seems that the issue of being able to work on (and apply effects to) an alpha by itself by way of some sort of "layer switch/toggle" would be kinda nifty to see in some future release of Æ. as far as getting premultiplication to work right for ya, well, i'm still just starting to get accustomed to that math...
;P
-stev=o

[Mike Drinks]

Hey Rick,

What you are describing though is final compositing. What if, (as is the case in Photoshop) I wanted to create a final product that had an alpha completely unrelated to the RGB? In Photoshop, I can take a black and white image or selection and save a new alpha channel. Imagine the mayhem if whenever I created a selection in Photoshop, the RGB automatically got chopped up or or otherwise changed as is the case with AE!

Even with multi layers you could create a circle in the alpha and a large overlapping square in the RGB as a final rendered quicktime movie from AE? If you can, please describe!
:)
Mike

[Rick Gerard]

The alpha channels in AE, whether created, rendered, or interpreted from footage, have no effect on the RGB portions of the image unless you choose to have the alpha control a chosen property of the rgb channels.

By default, AE assigns an alpha channel to all layers and interprets the alpha as a straight alpha. You can use the set channels filter to ignore if you wish to ignore the alpha or change the mode on a particular layer.

If you choose to Pre-multiply on rendering or interpreting footage, the original RGB values are still not changed. The only thing that happens is that the values in the chosen background color are pre-multiplied with the values in the RGB channels when computations are made blending those values with underlying layers.

There are problems with the plug-ins that are used to render TGA sequences and Tiff sequences that are basic to their formats which can cause problems when rendering 32 bit (rgb + alpha or “Millions +”) from within AE, but these problems are not unique to AE and are present in every other app that I’ve ever used.

[Zap Andersson]

Rick, JPEG's will do JUST FINE because they could just as well be the exact footage I use. Here we have an example:

The background:

The RGB data, properly premultiplied:

The alpha:

This is what AE gives me:

This is what I want to see:

The "problem" lies in the fact that AE does not understand premultiplied data unless it is embedded in ONE SINGLE file, a .tga or .avi/.mov with alpha channel.

There is NO WAY to get AE to understand premultiplied when it comes from separate files.

Furthermore, when we say that AE changes the RGB data (which you claims it does not) we are talking about the OUTPUT rgb of the layer. In a premultiplied system, input RGB equals output RGB of the layer, and what we put in is exactly what we want out, and alpha only governs the scale factor for the background ONLY, not the foreground. Alpha should NOT have an impact on foreground in premultiplied mode!!!!!!

/Z

[Rick Gerard]

The problem I see here is that your "pre multiplied” rgb and your alpha don’t match. The pre-multiplied RGB has black in the partially transparent pixels because the program you used to render these pixels added in black values. The alpha channel properly sets values for all pixels, but the white ones you want to add to the background are not white, but various shades of gray (and colors for the handle) because they have been mixed with the background layer.

If you simply screen the rgb layer over the background all of the white pixels will properly blend with the background. This is not an acceptable solution because of the colors at the end of the shaft of light.

If you use luma matte to extract an alpha channel from the rgb image, render the combination and import the footage with an alpha, and then choose luminescent premultiply as the transfer mode you’ll get exactly what you want.

Since I don’t have the app you used to render the rgb image,(I assume it’s a light saber) I cant exactly duplicate it, but I’d bet if you rendered as a straight alpha (not pre-multiplied) and then brought the pieces into AE as a rgb layer, an alpha layer, and your bg you’d get exactly what you have in the bottom frame. The problem with the files you posted is that the rgb image is pre-multiplied with the black and the rgb pixels are changed from their original color. Luminescent premultiply transfer mode is the only way to clean out the black. --- As I said before – it’s an alpha channel that wasn’t rendered properly.

[Zap Andersson]

The problem I see here is that your "pre multiplied” rgb and your alpha
don’t match. The pre-multiplied RGB has black in the partially transparent
pixels because the program you used to render these pixels added in black
values.

Exactly; That is precicely the proper appearance of a premultiplied file. Remember, in a premultiplied file, the RGB data already "looks correct".

One of the hundreds major advantages of premultiplied vs. straight, is that the RGB data is directly viewable and will look completely correct as the final image upon a black background.

This is all completely correct, and the flaw in handling this completely correct image lies within AE.

The alpha channel properly sets values for all pixels, but the white ones
you want to add to the background are not white, but various shades of
gray (and colors for the handle) because they have been mixed with the
background layer

Exacly - because it's *premultiplied*, Rick. Stop thinking in terms of Straight alpha.

In a straight alpha system, 50% transparent white (i.e. a color which in the final image ends up 50% gray and 50% of the background) is, in RGBA data (ranges 0-1) "1, 1, 1, 0.5", but in a premultiplied system, 50% transparent white is "0.5, 0.5, 0.5, 0.5".

You see ANOTHER of the hundreds of advantages of prem.alpha is that "all channels are created equal" and an operation you do to one, you do to them all. So to to make the pixel 50% transparent you simply divide ALL components (not just the alpha) by two.

It's Premultiplied! REAL alpha. The way God meant it to work :-) (Okay, just kidding, but the way Jim Blinn, Ed Catmull and Alvy Ray Smith, the people who actually invented the damned thing, meant it to work, and yes, I asked myself)

Since I don’t have the app you used to render the rgb image,(I assume
it’s a light saber)

It happens to be that, yes. Sorry for all my examples *incidentally* happen to be around lightsabers :-) pure coincidence actually.... don't go all elite on me just because I happen to be doing lightsabres.... but.... Rick... you [b]don't have 3D studio?[/b] I thought you said you did!

Here's how to get these results out of 3D studio:

1. make a really motion blurred object which is 100% self-illuminated.

2. Render it to a .JPG file or ANY other pure "RGB" format. *not* any format that inherently includes alpha.

3. In "Render Elements" in the Render dialog, render Alpha separately. Surely you done this some day? (I use render elements all the time to get my stuff in layers for compositing later.)

You will get files precicely as these.

/Z

[Rick Gerard]

There's no need to get rude here.

There's black added to the pixels you’re trying to lay over the background because you put them there in 3DS when you rendered pre-multiplied. Luminescent premultiply will remove the black and screen the lighter pixels properly over the bg layer.

You wanted a solution and I gave you one. Here is another one.

Place your alpha on layer 1 and turn off visibility. Place the rgb image on layer 2, and the background on layer 3. Apply Set Matte to the rgb image (layer 2) and pick layer 1 for the source. Choose luminance for the values, leave everything else at the default settings. Set the transfer mode to luminescent premultiply for layer 2 and you’ve got exactly what you show as the composite you want. You can add masks, pre-compose and collapse transformations, or do anything else you want with the layers now and everything will work.

I don’t own 3DSmax but I get files from other contractors all the time rendered from this program. Everything I get from them is rendered with straight alphas. Everything I render for online, AVID, or any other is rendered with straight alphas. It’s a better way to work.

By the way, if you put your background plate in 3dS and rendered premultiplied you’d end up with another mess because you can only premultiply using one color value from the background.

I’m not going to debate this anymore. You wanted a solution and I have given you two. If you want to write a plug-in ( I seem to remember that you said you have been programming for years in other posts) that separates out values in ranges, applies different transfer modes to the pixels masked by those ranges, or whatever you want AE to do with the alpha information then be my guest. The SDK is available for free from ADOBE. If you want to lobby Adobe for a major change in the way alphas are treated by default then be my guest. Write to them, get on the Beta team and argue your point. I haven’t got the time or energy to pursue this debate further.

[Zap Andersson]

There's no need to get rude here.

If you perceived what I wrote as rude, I apologize. It was intended a bit more "tounge in cheek" than rude, I must say!

Luminescent premultiply will remove the black and screen the lighter pixels
properly over the bg layer.

Luminicent premultipled has all sorts of buggy problems. And it's still *beside the point*. It's not a *solution*, it's a *work around*. "Umult" on the layer is more of a *solution* but it's embarresing that this doesnt exist in core AE!

I don’t own 3DSmax but I get files from other contractors all the time
rendered from this program. Everything I get from them is rendered with
straight alphas.

That's possible that, but you quite probably get it rendered with RGBA in a signle file, which AE interpretes correctly regardless of straight or premultiplied.

It’s a better way to work.

Why?

- the math is more complicated
- data in the RGB channels when alpha is zero is unused and wasted
- etc.

Please motivate this statement. Why is it better? And why is all the founding fathers of Computer Graphics not agreeing with you?

By the way, if you put your background plate in 3dS and rendered premultiplied
you’d end up with another mess because you can only premultiply using
one color value from the background.

THAT is quite true! But you don't.

If you want to lobby Adobe for a major change in the way alphas are treated
by default then be my guest.

I am. Havn't you noticed ;)

/Z

[Zap Andersson]

Set the transfer mode to luminescent premultiply for layer 2 and you’ve
got exactly what you show as the composite you want. You can add masks,
pre-compose and collapse transformations, or do anything else you want
with the layers now and everything will work.

You didn't actually try this, did you?

Try this. Then add a mask to the rgb layer. Nothign happens. Try adding a quick blur to the object layer. Instant mess.

For the record, though - If I do *pre compose* these layers and apply masks and blurs to the precomposite, it DOES work, however.

But isn't this an awful lot of hoops to jump through to get a simple thing right?

Wouldn't a simple checkbox for, say, "Set Channel" or "Track Matte" or whichever of them you choose that says "interpret rgb data as premultiplied" be a lot easier on everyones hair?!?!?!

/Z

[MythProd]

Zap, after effects isn't your only compositing option. I'm wondering if there's any compositor in existence that will handle alphas the way you like.

[Joseph Francis]

The whole alpha channel thing, one more time. <http://www.digitalartform.com/alphaChannel.htm>

Comments? Corrections?

[Mike Drinks]

Looks right to me Joseph. After Effects can do anything as long as you finish in After Effects. If you want to render animated elements for flexible compositing elsewhere, you have to jump through many hoops and accept that AE can't create "...RGB values that are intentionally decoupled from the alpha values..." This is a problem if your compositing down the line on a Non Linear Editor that does not have math compositing capability, like Sphere or older Avids.

Well said Joseph!

Mike

[Zap Andersson]

Well written!

I especially like the phrasing about "combating the unnecessary multiply with an equally unnecessary divide", which is precicely the hoops one is left to jump through to get this stuff right.

Straight alphas makes sense ONLY when the originating data comes from a real world image out of which you want to *extract* something.... straight alphas does not make sense when you already have a proper image with proper RGB data in it, i.e. when it comes from a computer rendering software. There only "premultiplied" makes sense. Making the file 'straight' by imposing the 'needless divide' is an UGLY KLUDGE FIX stinking of bad workaround slime so bad that one never, as a rendering software developer, should have to contemplate doing, yet have been forced to do for decades due to bad compositing software coders only thinking about 'real world' originating imagery!!!

/Z

[Jim Howells]

Hey Zap,

I don't know if this might solve your single layer problem. Steven Walker has a plugin called Composite. It's $20. It has alpha tools and and all of AE's transfer modes in an effect. Which means that you can apply the Lumenisent Premultiply and effects to the same layer. I tried it out on some the sample images you've posted and it seems to do the job.

<http://www.walkereffects.com>

You should check it out.

[-stev=o]

jim,
those are some most excellent plugs. thanx for the tip. stargate is cool!

-stev=o

[Zap Andersson]

Jim, I bet that is really useful. But it's not the point. The point is, that everything is a workaround, while this shuld be the most basic bread-and-butter functionality of AE.

You can "do" this in a million ways with various workaround. You shouldn't have to. THAT is the point.

/Z

[Jim Howells]

I'm not going to debate you on what should be in AE or not.

I thought you were looking for a method to do it in a comp with only two layers a foreground and background. Using you're graphics. I tried with the files in this thread and seemed to have gotten the result you are looking for, and the plugin is only $20.

I thought that was the point you didn't want to have 3 layers or to have to apply the alpha to the background.

As for your assertion that this should be a bread and butter function of AE, why is that so many here have had to have the problem pointed out to them? Would it not have been readily apparent to them?

(Sigh) I don't know, I guess you've got a point about AE working internally only as straight alpha. All I can say is that this has never been an issue for me. Yes I do composite 3D graphics into AE. But again I've never rendered 3D and it's alpha separatly. The file had the alpha with it.

Jim

[Rick Gerard]

Luminiscent premultiply is the key to accomplishing the same thing as Shake's REB/A node and solving this problem completely in the compositing stage.

The only probelm that exists using this transfer mode is a render pipeline issue. Don't expect Adobe to sit on their render pipeline issues forever.(basic text for example) I expect that it will be solved in the near future.

[Bob Maple]

Set the alpha as a Luma track matte for the RGB. Select both and precompose them to make them appear as 1 layer with an alpha, like you want.

Now add the "Remove Color Matting" effect to the precomposed layer, and select black.

This will "un-premultiply" your 3D output, the same thing that would happen if you had the alpha embedded in a movie and could select that in the interpolation settings for the footage.

[Zap Andersson]

As for your assertion that this should be a bread and butter function
of AE, why is that so many here have had to have the problem pointed out
to them? Would it not have been readily apparent to them?

Because, for decades, rendering software people have been forced to output mangled data (i.e. "straight alpha" junk) to comply to the mangled behavior of compositors.

It's just that it's unelegant. It's a workaround on top of a workaround already. It's ugly. It's bad. It's wrong. It stinks :)

I like elegance and simplicity, and that is what I would like. Just a toggle on a layer to tell the layer to behave in a premultiplie manner would be a start. Or a toggle in the comp to behave in proper premultiplied mode, for example.

/Z

[Bob Maple]

Well clearly you just want to sit here and bitch about this as opposed to getting your work done, so knock yourself out.

[igorstshirts.com]

Zap,
If whatever You are saying is true, than that was a funny post!

[Paul Monson]

Zap,
If you rendered your RGB AVI file with a black background then that is what your seeing around the edges of your composite, not the alpha being premultiplied with the RGB image or whatever you said. You have to understand how an alpha channel works in conjunction with antialiasing. You see, when you rendered your original on a dark background the antialiasing multiplies with the black in the BG and causes grey colored pixels where there would be transparency. When you use the alpha info, the antialiasing in the alpha takes those pixels at a lesser value than 100%, but those pixels are no longer white or light. They have been multiplied beforehand, or premultiplied with the dark background. THATS WHY WE USE STRAIGHT ALPHAS IN THE PROFESSIONAL WORLD, and I'm glad your not my employee rendering 2x as many files as you need.

[Zap Andersson]

If you rendered your RGB AVI file with a black background then that is
what your seeing around the edges of your composite, not the alpha being
premultiplied with the RGB image or whatever you said.

This is straight alpha thinking.

You have to understand how an alpha channel works in conjunction with
antialiasing.

I understand perfectly well how an alpha channel works in conjunction with antialiasing, both straight and premultiplied style. You show clear indication of only understanding straight style.

You see, when you rendered your original on a dark background the antialiasing
multiplies with the black in the BG and causes grey colored pixels where
there would be transparency.

That is a straight alpha interpretation. My interpretation is that it causes a gray pixel PLUS transparency (in the alpha channel). The gray pixel is correct, heck, if the pixel is halfway covered with a white object it shuld be 50% gray, shuldn't it? So why make it 100% white and 50% in the alpha? Doesnt make sense. Make it 50% gray as it should, and put the 50% of transparency in the alpha. That's how premultiplied alpha works. Makes a lot more sense and makes your RGB data immediately viewable as-is with a correct image.

When you use the alpha info, the antialiasing in the alpha takes those
pixels at a lesser value than 100%

But in the premultiplied world the alpha value ONLY tells us how much background to let through, nothing else. The alpha does not affect the foreground RGB data at all when compositing.

Not only is this faster to calculate (less multiplications), it's more useful (your image has the correct RGB data for direct viewing), it also allows the extended gamut of semi-additive comping (but nobody seems to care about this fantastic feature, sigh)

THATS WHY WE USE STRAIGHT ALPHAS IN THE PROFESSIONAL WORLD

ILM always works with premultiplied alpha, you know. Their own OpenEXR file format for high dynamic range images defines alpha as premultiplied.

, and I'm glad your not my employee rendering 2x as many files as you
need

That's a storage issue, I am using the best compression on each type of imagery. And they are rendered at once, so there is no extra time taken, and the space is smaller.

/Z

[Paul Monson]

Zap,

No, I fully understand how a white pixel at 50% transparency will appear 50% grey against a black background. Make two layers in photoshop, 1 white and 1 50% grey. Now turn down the opacity to 50% and see if those two colors are the same. Needless to say, they are not. An alpha is a greyscale representation of transparency only. If there is a pixel in the antialiasing that is 50% white in the alpha, that means it will choose 50% of the pixel in the corresponding RGB image. If that color is white (straight alpha) it will be like turning down the opacity to 50% on a white layer. If you premultiplied your original on a dark background you will see a dark ring and complain about AE on this forum. I'm not sure why you think straight alpha channels are the devil when they look the best when brought back into pretty much any compositing software out there. When do you use an element with an alpha channel before compositing it? I work in TV, so its never a worry. Everything we put into our Avid systems has a straight alpha cause it looks better when composited, and thats all that matters to our company.

[Zap Andersson]

When they work and are used correctly, straight alpha and premultiplied alpha looks identical, so there is no "looks better" about straight alpha.

The problem is that you insist on thinking about a black background, where I refuse to do so. This "premultiplied with 'insert color here'" is ANOTHER spawn of the devil, you know.

The background in a proper premultipled file is not "black", it is a NULL background. It has no color. It is a void. The void has no R, G, B or Alpha.

The thinking that I "already multiplied my file with a black background" is inherently flawed thinking, is conceptually wrong. This has not occured. Again it's that badly chosen name "pre-multiplied" creaping up inducing in our brain a falsehood.

What I have is a file containing the proper RGB data over the proper Alpha mask, where the alpha when composited will apply to the background only. I have to say this again to let it sink in, premultiplied alpha only defines the amount of transparency the pixel has, i.e. the percentage of BACKGROUND needed. It has NO impact on foreground. It applies to the background ONLY.

ILM uses premultipled alpha. Pixar uses premultiplied alpha. I can hardly think of any REALLY big boy who willingly uses straight alpha other than those who are "forced" to do so by using crappy software that insists on using it (i.e. AE).

And yes, I attest that in perhaps 85% or even 90% of your run-of-the-mill compositing work it doesn't matter which you use, as soon as your application can interpret it correctly.

My problem with AE in this regard are these:

1. AE can only "understand" premultiplied alpha (semi)properly when it comes in as ONE file. If you, for whatever reason, have them separate, you have to jump up and down and in circles to get AE to actually understand the data.

2. PROPER interpretation of a premultiplied file is the composite equateion (comp = fg + (1 - alpha) * bg) and this gives us a WHOLE GAMUT of additive and semi-additive compositing FOR FREE which AE does not support in any way, except partially and very poorly, using the "Luminecent premultipled" transfer mode. And note that AE programmers have the glorous NERVE to call this whole gamut of functionality "illegal". That's pretty hilarious.

ILM is on my side. Pixar is on my side. The guy who invented alpha channels, Alvy Ray Smith, is on my side. Who else do I need?

/Z

/Z

[Jeff Bellune]

<yawn>

[Joseph Francis]

Zap -- you need to either drop AE and use something like Shake, or use AE but do the multiplies and adds yourself in explicit multiple steps (I assume this is possible in AE?)

Paul -- one long "word" for you:
<http://www.digitalartform.com/alphaChannel.htm>

[tonytse]

Hi guys ; use 3dsmax too, just export your movie in QuickTime, million colors +. thats it! u gonna have ur logo fly on ur bg layer with transparent..
or.. i missunderstand the topic..im sorry. :S

tony

[Jim Howells]

Tony, yeah you misunderstood. You'll have to find all of Zap's Alpha threads to see what he's talking about.

[jmhemanth]

think you guys have not seen a filter present in the cnannel sub category --------remove color mating---this works fine even when people dont interpret alpha properly

[Rick Gerard]

Zap ... The render pipeline problem with the luminescient premultiply transfer mode has been fixed in AE 6.0. As far as I can tell you can do exactly what you want to do with a single layer. No pre-composing/collapse transformations conflict now.

[Zap Andersson]

Radical!

* kisses to Adobe*

Just have to check my wallet.

* moths fly out*

:(

/Z