home
***
CD-ROM
|
disk
|
FTP
|
other
***
search
/
Amiga Plus 1995 #5 & #6
/
Amiga Plus CD - 1995 - No. 5 and 6.iso
/
pd
/
grafik
/
lightwave
/
lightwave-jan95
/
000361_owner-lightwave-l _Mon Jan 30 10:34:58 1995.msg
< prev
next >
Wrap
Internet Message Format
|
1995-02-04
|
2KB
Return-Path: <owner-lightwave-l>
Received: by mail3.netcom.com (8.6.9/Netcom)
id GAA06061; Mon, 30 Jan 1995 06:33:08 -0800
Received: from mv.mv.com by mail3.netcom.com (8.6.9/Netcom)
id GAA05560; Mon, 30 Jan 1995 06:30:52 -0800
Received: by mv.mv.com (8.6.9/mv(b)/mem-940616)
id JAA20421 for lightwave-l@netcom.com; Mon, 30 Jan 1995 09:31:51 -0500
Received: by fusion.mv.com (V1.16/Amiga)
id AA003bh; Mon, 30 Jan 95 03:17:01 EST
Date: Mon, 30 Jan 95 03:17:01 EST
Message-Id: <9501300817.AA003bg@fusion.mv.com>
Message-Id: <20201b2a.493eb-mark@fusion.mv.com>
In-Reply-To: <9501291429.1.13416@cup.portal.com>
(from Jeric@cup.portal.com)
(at Sun, 29 Jan 95 14:29:53 PST)
X-Mailer: //\\miga Electronic Mail (AmiElm 4.159)
From: mark@fusion.MV.COM (Mark Thompson)
To: lightwave-l@netcom.com
Subject: Re: alpha's
Sender: owner-lightwave-l@netcom.com
Precedence: bulk
Jeric@cup.portal.com writes:
> >Lens flares are an additive effect, ie. adding them to some image should
> >not in any way diminish the intensity contribution of any pixel.
> This is good for compositing within the computer, but what if
> you are trying to composite an animation WITH lens flares off a
> tape in a post-production suite?
You are SOL!
> Your reply seems to imply that this would not work, directly using
> the alpha-channel animation generted by Lightwave thru ALPHA-SAVE.
That is correct. Unless you have video hardware that can perform an
absolute add of your flares to your other video material, this method
does not work. In which case you must resort to using fader alpha. Once
again, this was all explained in my LWPro article, but....fader alpha
divides each output RGB pixel by alpha so that when external compositing
is done, transparent surfaces are properly handled. Unfortunately, there
is no way to properly deal with additive effects like flares. Instead,
they are treated like transparent surfaces which is incorrect, but about
the best you could do. Another disadvantage is that you lose your lens
flare color when using fader alpha.
*~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~*
* Mark Thompson (603) 424-1829 *
* Fusion Films Inc. mark@fusion.mv.com *
* Radiant Image Productions *
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~