From: "Chris Zwar" Received: from mail-pl0-f54.google.com ([209.85.160.54] verified) by media-motion.tv (CommuniGate Pro SMTP 6.1.0) with ESMTPS id 6437650 for AE-List@media-motion.tv; Wed, 18 Apr 2018 01:32:01 +0200 Received: by mail-pl0-f54.google.com with SMTP id w12-v6so11961677plp.0 for ; Tue, 17 Apr 2018 16:37:35 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=chriszwar-com.20150623.gappssmtp.com; s=20150623; h=from:mime-version:subject:date:references:to:in-reply-to:message-id; bh=UAu+3YtAO9QbB6tM1LmwI2sBpLlFxCouTxX/NqerfJk=; b=1GGOI3CO4PsssaGwhM8uF7k8nGQaXurRECUf/FTq/s6o5zXbZbIBvPhT2owOCXU0tl UFWtL6iM7SsTdDX8wLi6ADXLs97Q5CM7F1sKzrUEXm27LF6h4/BKsKPghEY4to6NGwkX g9oF2suJfPmPV/wZC7FSCHfvVwdN+OUR483EwMHwBSA36Vlr9LWNWKlRp8lU7/8uA92o VoovXePi6sKP2bOGEbcyHreKLMVq2q2wOOTdZQkeu1NFDC4XdiReM2g05Ra0uAUxtmQl xCtmRMhfRcjU0n+5FwQWyVK4OZUksh6YvOXB9YgUn05OTYL8Ji0f/sQXYVltcxfkLXdC BDbg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:mime-version:subject:date:references:to :in-reply-to:message-id; bh=UAu+3YtAO9QbB6tM1LmwI2sBpLlFxCouTxX/NqerfJk=; b=TpNcZTCgnaaHZqLkRmpC+OYJeHw08xG/hjy/6suWR9EnnHukS1/kcfCyhXGW/ktbzU fi6FW12dN7z1m17kAYJxEQ7b096IXBnAFJ5BamfuULuzKawwS59kGosmrV/ESADxueVj Qvu6+flG5JnjHI+gqg4TAkt2y/E5k4GslENLtWIKJVbd7cTu6zihaL9AMnlAZw+6rccs tl+Zv6xrkbsFYgDFM6Flxa7Yys18vk0G+ISbfhxqIUNXCdtG5/lVE5InkJ3m0DarfjEB 6RBTkSusdqD7K3vUA5GUsXaqgDfq0D321Pxf6jLjJfWs1+UIZIOtRnaFPpMxvYNNlXYM qxUg== X-Gm-Message-State: ALQs6tBleHQ3ekyKQwkZkREge7rQHbrO/PLYhBCiR56g81UVUsul2ACt B/nHlbJyR60Q5jlCYWMbv6yqFryoKEM= X-Google-Smtp-Source: AIpwx4+K3BIDLFyoitLn2nPSU68jMwdIJAIqn0S9IMor0Mv0iuTWCG4iTYYMra+ih8ZHDYLAnOgdQg== X-Received: by 2002:a17:902:688c:: with SMTP id i12-v6mr3778375plk.166.1524008253398; Tue, 17 Apr 2018 16:37:33 -0700 (PDT) Return-Path: Received: from [192.168.3.137] (220-244-139-34.static.tpgi.com.au. [220.244.139.34]) by smtp.gmail.com with ESMTPSA id m21sm28101702pgn.0.2018.04.17.16.37.31 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Tue, 17 Apr 2018 16:37:32 -0700 (PDT) Content-Type: multipart/alternative; boundary="Apple-Mail=_BD14D31B-1489-479B-8158-AD9FC92A0A1F" Mime-Version: 1.0 (Mac OS X Mail 11.3 \(3445.6.18\)) Subject: Re: [AE] Inverse Square Law for glows Date: Wed, 18 Apr 2018 09:37:29 +1000 References: To: After Effects Mail List In-Reply-To: Message-Id: X-Mailer: Apple Mail (2.3445.6.18) --Apple-Mail=_BD14D31B-1489-479B-8158-AD9FC92A0A1F Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset=utf-8 If you want to do it mathematically then it=E2=80=99s more complex than = you think, as you need to consider the gamma of the workspace you=E2=80=99= re using. Making something glow by stacking up multiple layers with different = blurs is faking it, but probably the best way to do it in 8 or 16 bit = modes. It=E2=80=99s the way i do it too, although I use the screen mode = (not add), and I usually have a desaturated layer near the top set to = classic colour dodge to adjust the =E2=80=9Chotness=E2=80=9D. =46rom a = mathematical perspective, you=E2=80=99re not just looking at the blur = profile but also the gamma of the workspace so this multiple layer = approach is going to be difficult to calculate. The alternative approach is to comp in 32 bit linear mode, where you = don=E2=80=99t need to stack up multiple layers. You just have your = source layer and make the colour super hot. Then you blur it and the = blur naturally spreads out the light. The falloff will depend on the = type of blur you use. I did ask a while ago (for exactly the same = reason as you) if there=E2=80=99s a blur with an adjustable profile = including inverse square, which would be very useful for comping glows = in 32 bit float mode. I can=E2=80=99t remember the answer, but = there=E2=80=99s something for you to look at. So basically - multiple layers using add/screen and blur is an 8/16 bit = fudge for a gamma working space like sRGB/HDR. A single, super hot = layer with a single blur in 32 bit linear float is the more natural = approach. Or you can just use a plugin that does it, as lloyd suggests :-) -Chris > On 18 Apr 2018, at 4:28 am, Byron Nash = wrote: >=20 > So, if I were applying that to say, the blur of a layer, what would be = the "distance" variable? I'm stacking several layers with Add transfer = modes and variable amounts of blur. >=20 > On Tue, Apr 17, 2018 at 2:17 PM Walter Soyka > wrote: > The inverse square law states that intensity is inversely proportional = to the square of the distance from the source. Symbolically: > intensity =3D 1 / (distance^2) >=20 > Doing a little math, when the distance is 1, the intensity is 1. When = the distance is 2, the intensity is 0.25. When the distance is 3, the = intensity is 0.111. When the distance is 4, the intensity is 0.0625. >=20 > walter soyka =E2=96=BC keen live=20 > walter@keenlive.com >=20 > On Tue, Apr 17, 2018 at 1:46 PM, Byron Nash > wrote: > Always the consummate salesman Lloyd! ;-)=20 >=20 > I think this was more of an experiment to see if I could do it myself = and understand the math a bit better.=20 >=20 > On Tue, Apr 17, 2018 at 1:05 PM Lloyd Alvarez > wrote: > Oooooorrrr you could just use Real Glow = ! ;-) >=20 > Cheers, > Lloyd >=20 > On Tue, Apr 17, 2018 at 12:16 PM, Byron Nash > wrote: > I'm trying to roll my own setup for a better glow. If I'm trying to = follow the inverse square law to do the math, would I half/double the = amounts at each iteration? Or square root? >=20 >=20 --Apple-Mail=_BD14D31B-1489-479B-8158-AD9FC92A0A1F Content-Transfer-Encoding: quoted-printable Content-Type: text/html; charset=utf-8 If = you want to do it mathematically then it=E2=80=99s more complex than you = think, as you need to consider the gamma of the workspace you=E2=80=99re = using.

Making = something glow by stacking up multiple layers with different blurs is = faking it, but probably the best way to do it in 8 or 16 bit modes. =  It=E2=80=99s the way i do it too, although I use the screen mode = (not add), and I usually have a desaturated layer near the top set to = classic colour dodge to adjust the =E2=80=9Chotness=E2=80=9D.  =46rom= a mathematical perspective, you=E2=80=99re not just looking at the blur = profile but also the gamma of the workspace so this multiple layer = approach is going to be difficult to calculate.

The alternative approach is to comp in = 32 bit linear mode, where you don=E2=80=99t need to stack up multiple = layers.  You just have your source layer and make the colour super = hot.  Then you blur it and the blur naturally spreads out the = light.  The falloff will depend on the type of blur you use. =  I did ask a while ago (for exactly the same reason as you) if = there=E2=80=99s a blur with an adjustable profile including inverse = square, which would be very useful for comping glows in 32 bit float = mode.  I can=E2=80=99t remember the answer, but there=E2=80=99s = something for you to look at.

So basically - multiple layers using = add/screen and blur is an 8/16 bit fudge for a gamma working space like = sRGB/HDR.  A single, super hot layer with a single blur in 32 bit = linear float is the more natural approach.

Or you can just use a plugin that does = it, as lloyd suggests :-)


-Chris
On = 18 Apr 2018, at 4:28 am, Byron Nash <AE-List@media-motion.tv> wrote:

So, if I were applying that to say, the blur of a layer, what = would be the "distance" variable? I'm stacking several layers with Add = transfer modes and variable amounts of blur.

On Tue, Apr 17, 2018 = at 2:17 PM Walter Soyka <AE-List@media-motion.tv> wrote:
The inverse square law states = that intensity is inversely proportional to the square of the distance = from the source. Symbolically:
intensity =3D 1 / = (distance^2)

Doing a = little math, when the distance is 1, the intensity is 1. When the = distance is 2, the intensity is 0.25. When the distance is 3, the = intensity is 0.111. When the distance is 4, the intensity is = 0.0625.

walter soyka =E2=96=BC keen live 
walter@keenlive.com

On Tue, Apr 17, 2018 at 1:46 = PM, Byron Nash <AE-List@media-motion.tv> wrote:
Always the consummate salesman Lloyd! ;-) 

I think this was more of = an experiment to see if I could do it myself and understand the math a = bit better. 

On Tue, Apr 17, 2018 = at 1:05 PM Lloyd Alvarez <AE-List@media-motion.tv> wrote:
Oooooorrrr you could just use Real Glow! ;-)

Cheers,
Lloyd

On Tue, Apr 17, 2018 at 12:16 = PM, Byron Nash <AE-List@media-motion.tv> wrote:
I'm trying to roll my own setup for a better glow. If I'm = trying to follow the inverse square law to do the math, would I = half/double the amounts at each iteration? Or square root?



= --Apple-Mail=_BD14D31B-1489-479B-8158-AD9FC92A0A1F--