POV-Ray : Newsgroups : povray.documentation.inbuilt : Default values in v3.8.0 : Re: Default values in v3.8.0 Server Time
7 Dec 2021 14:30:43 EST (-0500)
  Re: Default values in v3.8.0  
From: clipka
Date: 20 Sep 2018 17:47:06
Message: <5ba4155a$1@news.povray.org>
Am 20.09.2018 um 22:19 schrieb Kenneth:
> clipka <ano### [at] anonymousorg> wrote:
>> In POV-Ray v3.8.0, default values will be chaned as follows:
>>
>> - The `ambient` setting now defaults to zero instead of 0.1.
> 
> Great! Nice and consistent with the other newer finish defaults.

Um... what other newer finish defaults?


>> - The default pigment is now plain white (rgb <1,1,1>) instead of black.
> 
> I''m curious about the reason for this change. (Personally, it will take some
> getting used to.) Is it perhaps due in some philosophical way to the change of
> #default ambient to 0.0 (where pure shadows would now be pure black instead of
> 'lit' with ambient 0.1? Meaning, it would be hard to discern a previously
> un-pigmented object-- black until now-- from it's now-black shadow duo to
> ambient 0.0?)

Since ambient is also multiplied with pigment, traditional default was
pitch-black and thus invisible.

The rationale is simply that hey, the default of pitch black is of no
practical use /at all/ - white, on the other hand, eliminates one of the
N things that you have to do to see /anything/ at all. Those used to be:

(1) Place at least one object in your scene.
(2) Place your camera somewhere outside the object.
(3) Aim your camera at the object.
(4) Place a light source somewhere reasonable outside the object.
(5) Give your object a pigment that isn't pitch black.

(Alternatively to (5), you could also (5a) Set up a background or sky
sphere that isn't pitch black, but that isn't nearly as satisfying.)

With white default pigment, we're only left with steps (1)-(4) for a new
user to produce their first remotely satisfying image.

Also, white makes for nice images if you're really just interested in shape.


>> - The camera `right` vector length now defaults to the output image
>> aspect ratio (presuming square pixels; for example, at 1280x1024 the
>> vector will have a length of 1,25) instead of 1.33. The rules governing
>> the direction of the vector remain unaffected.
>>
> 
> I don't usually mess with   right  x*image_width/image_height,  and run
> different aspect-ratio images simply by choosing another entry in quickres.ini.
> (1280X720 instead of 800X600, for example.)  Will this change affect the visual
> result of the render (in some *strange* way), if I continue to use my simple
> scheme? Sorry if my question seems naive, but it's not clear if my quickres.ini
> entries would also need changing.

Presuming that by "I don't usually mess with..." you mean "I usually
use..." (as opposed to e.g. "I don't even try to use..."), there's no
need to worry.

First of all, as long as you explicitly specify a "right" vector,
nothing changes at all. User-specified "right" wins over default, as
previously.

And second, "right x*image_width/image_height" is in fact exactly what
the new default boils down to.


Post a reply to this message

Copyright 2003-2021 Persistence of Vision Raytracer Pty. Ltd.