#Missing Alpha
4 messages in this thread
Folks,
I think I am getting to the root of the ambiguity of alpha channels; it's the
interpretation of the words based on its use. The issue of differing opinions
about alpha channels seems to be again in the chasm between the video world and
the computer world. Video people, for example means that if the alpha channel
is on, the whole image has an alpha value of 255 and only the edges have 8-bit
gradations over a black background. For the computer people that I talked with
(such as ILM special effects programers, game developers, etc.), the alpha
channel should represent alpha throughout the image — not limited to the edges
of objects over black backgrounds. So, the confusion over my missing alpha
channel seems to be based on the point of view. And because my clients want a
computer-oriented alpha channel, I must first render the image in 3DS, then go
into QFX and create an alpha channel and save the new corrected image. Unless
there is a better way.
Any suggestions?
-Gregory MacNicol
Gregory,
<< where's my alpha..>>
Since you want a computer "view" of alpha, why do you
feel that you must go to another package to create it.
See pg. 8-139 of the ref. manual to see how 3ds can
create an alpha data throughout the image for you.
jonas[adesk]
According to Alvy Ray Smith (one of the inventors of the alpha channel), an
alpha channel should always put 255 into the opaque area, 0 into the completely
clear area, and a gradient in between. There is absolutely no standard for
doing it the other way. If you can find a published article about doing it the
other way, I'd love to see it.
Note that our alpha channels work perfectly for doing everything from using it
in Photoshop, Altamira Composer, etc, to using them as matte elements in an
ABC-roll environment.
– G
I just wanted to second what Gary's saying and agree that 3DS alpha
works just fine for me. I've used alpha channel manipulations for
video as well as other app's for years. My recently uploaded image
"RUBE.jpg" is a test mock-up frame from an animation I'm working on
and used 5 layers composited from 3DS – it worked fine and as
expected.