POV-Ray : Newsgroups : povray.documentation.inbuilt : PIGMENT documentation-- a minor clarification Server Time: 18 Jan 2019 01:15:38 GMT
  PIGMENT documentation-- a minor clarification (Message 1 to 3 of 3)  
From: Kenneth
Subject: PIGMENT documentation-- a minor clarification
Date: 12 Nov 2017 19:45:00
Message: <web.5a08a3b02433197289df8d30@news.povray.org>
I have a small nit-pick about the in-built documentation at "2.3.5.1 Pigments"
within the first paragraph. (It's also in the online wiki, in "Tutorial Section
3.3", under "Advanced Texture Options / Pigments"...

http://wiki.povray.org/content/Documentation:Tutorial_Section_3.3#Gamma_in_Legacy_Scenes

Both places say this:
"Pigments can also be layered one on top of the next so long as the uppermost
layers are at least partially transparent so the ones beneath can show through."

As this is mentioned as a 'general' statement in the very first paragraph, and
before any qualifications are given, a naive or new-user might naturally assume
that the following construct is a nice way to get, for example,  a sort of
color-filtered bozo effect.(I'm using specific pigments to clarify the point)...

texture{
pigment{bozo}
pigment {rgbt <.2,.5,.7,.5>
......

But that doesn't work-- the second pigment completely overrides the first, which
could be a frustrating surprise-- because adding pigments together this way is
not what is really meant by the doc's initial description *as it stands*. (Only
later in the docs is the pigment_map introduced, and/or multiple textures, which
are the correct methods of using/overlaying multiple pigments.) BTW, I was
tripped up by this too, when I first started using POV-Ray.

I would suggest a simple addition to the end of the documentation's sentence,
maybe in parentheses: "See "Using Transparent Pigments and Layered Textures"
below."  That should remove any mystery.


Post a reply to this message

From: Jim Holsenback
Subject: Re: PIGMENT documentation-- a minor clarification
Date: 13 Nov 2017 01:40:26
Message: <5a08f80a$1@news.povray.org>
On 11/12/2017 2:41 PM, Kenneth wrote:
> I have a small nit-pick about the in-built documentation at "2.3.5.1 Pigments"
> within the first paragraph. (It's also in the online wiki, in "Tutorial Section
> 3.3", under "Advanced Texture Options / Pigments"...

that's because they are one in the same ...

> 
>
http://wiki.povray.org/content/Documentation:Tutorial_Section_3.3#Gamma_in_Legacy_Scenes

huh?!?

> 
> Both places say this:
> "Pigments can also be layered one on top of the next so long as the uppermost
> layers are at least partially transparent so the ones beneath can show through."

only in one place on that page ...

> I would suggest a simple addition to the end of the documentation's sentence,
> maybe in parentheses: "See "Using Transparent Pigments and Layered Textures"
> below."  That should remove any mystery.

http://wiki.povray.org/content/Documentation:Tutorial_Section_3.3#Pigments


Post a reply to this message

From: Kenneth
Subject: Re: PIGMENT documentation-- a minor clarification
Date: 13 Nov 2017 16:15:01
Message: <web.5a09c4c72b45531989df8d30@news.povray.org>
Jim Holsenback <spa### [at] nothanksnet> wrote:
> Kenneth wrote...
> > (It's also in the online wiki, in "Tutorial Section
> > 3.3", under "Advanced Texture Options / Pigments"...
> >
> > http://wiki.povray.org/content
> > /Documentation:Tutorial_Section_3.3#Gamma_in_Legacy_Scenes
>
> huh?!?
>

Sorry; when I came to the 'Tutorial 3.3' section looking for 'Pigments', I must
have taken a detour into 'Gamma In Legacy Scenes' first (before reading further
down about 'Pigments') and posted the gamma link instead. Yeah, *I* thought the
link looked odd too!

>
> http://wiki.povray.org/content/Documentation:Tutorial_Section_3.3#Pigments

Looks good. Many thanks! (This little nit-pick has actually been on my mind for
a l*o*n*g time.)


Post a reply to this message

Copyright 2003-2008 Persistence of Vision Raytracer Pty. Ltd.