web.3ece265547d3238c109cfda10@news.povray.org...
> Thanks everyone for your views, all of which are good and solid
reasonings.
> BTW, is there a good repository to get photorealistic povray files to test
> out?

The main sources for Pov-Ray scene files (photorealistic or not) are:
- the "advanced" directory of the official Pov-Ray distribution
- the two "scene-files" (text and binaries) groups in this forum
- the www.irtc.org site (many Pov-Ray images are given with a more or less
functional scene code)

Users' sites often contain full scenes :
Jaime Vives Piqueres' http://www.ignorancia.org/galleries.php
My own site : http://www.oyonale.com/ressources/english/ (scroll down to
"macros and sources")
See also a (far from exhaustive, still in the process to be completed) list
of such sites here:
http://www.oyonale.com/ressources/english/tools.htm#POV-Ray


G.

--

**********************
http://www.oyonale.com
**********************
- Graphic experiments
- POV-Ray and Poser computer images
- Posters

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Welcome Daniel.

I have not tried Virtual Light, but POV-Ray is an extensive language with 11
years background. Many people have contributed to POV-Ray over the years. It
has a large fan-base.

> there are times that I found Virtualight do provide features
> that are more readily available, such as the use of sunlight
> as a light source. How do I achieve the same effect in POVRay?

Some features may be readily available in Virtual Light, but when you get to
know POV-Ray, there are a lot of "plugins" that I think it will turn around
the picture for you. They are usually called "include files" or "macros".
Regarding your sunlight question, I'll need a bit more information before
I'm sure what you're after. But if you want to use "real" objects or skies
as light sources, try radiosity (for diffuse reflections) and the
"reflection" keyword on objects where you want specular reflection from the
sun.

Regards,
Hugo

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"ABX" <abx### [at] abxartpl> wrote in message:
> I'm not really sure what kind of repository you are looking for but
perhaps this
> link can give you some applicable set of url:
> http://news.povray.org/01gv9v4o1177kqc94s30seukipp9rbfk22%404ax.com
>
> ABX

Wow those looks great!  Thanks.  The spice bottle one is amazing.

Daniel.

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"Gilles Tran" <tra### [at] inapginrafr> wrote in message:
> The main sources for Pov-Ray scene files (photorealistic or not) are:
> - the "advanced" directory of the official Pov-Ray distribution
> - the two "scene-files" (text and binaries) groups in this forum
> - the www.irtc.org site (many Pov-Ray images are given with a more or less
> functional scene code)
>
> Users' sites often contain full scenes :
> Jaime Vives Piqueres' http://www.ignorancia.org/galleries.php
> My own site : http://www.oyonale.com/ressources/english/ (scroll down to
> "macros and sources")
> See also a (far from exhaustive, still in the process to be completed)
list
> of such sites here:
> http://www.oyonale.com/ressources/english/tools.htm#POV-Ray

Thanks for the links.  BTW, I downloaded your wet bird scene file (aka
gt_city.zip) from irtc.  It is absolutely gorgeous.  There seems be
different pov file for each objects.  Does complex scene normally built from
rendering objects separately and then piece them together or am I getting
really confuse here?

Daniel.

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"Hugo Asm" <hua### [at] post3teledk> wrote:
> Some features may be readily available in Virtual Light, but when you get
to
> know POV-Ray, there are a lot of "plugins" that I think it will turn
around
> the picture for you. They are usually called "include files" or "macros".

Can you please recommend a good source for large collection of plugins?
Thanks.

> Regarding your sunlight question, I'll need a bit more information before
> I'm sure what you're after. But if you want to use "real" objects or skies
> as light sources, try radiosity (for diffuse reflections) and the
> "reflection" keyword on objects where you want specular reflection from
the
> sun.

Quoting from Virtualight manual:
"Sunlight is part of the global illumination method provided by VirtuaLight
Interface, allows open sky renders of the scene using environment lights.
Sunlight automatically controls the position of the sun in the sky dome
according to a time value. It can cast sharp shadows or extremely soft
shadows, but it only has effect when skylight is enabled.  SkyLight enables
the simulation of diffuse solar radiation using a quasi Monte Carlo
ray-tracing algorithm. This skylight is treated as a
large hemispherical direct light source at infinity also named sky dome. It
completely surrounds the world and doesn't cast any shadow."

SkyLight (int samples, rgbexpr color, float brightness) where:
samples: the number of ray samples to cast at each intersection point in
order to estimate irradiance; and

SunLight (int hours : int minutes, int samples, float brightness, rgb color)

Daniel.

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Daniel Ngu wrote:
   Since I'm a new comer, would you please let
> me know if you had tried out Virtualight as well and what you think of it
> and how it differs from POVRay.   
>    I have been going through the Virtualight's manual, one note I'll like to
> make is how similar its language is to POVRay.  

You did better than me, I'll be darned if I could find the manual.



   However, there are times
> that I found Virtualight do provide features that are more readily
> available,
> such as the use of sunlight as a light source.  How do I achieve the same
> effect in POVRay?
> 

With POV-Ray, instead of a canned effect, such as sunlight, being 
readily available, there is instead a devoted community endlessly 
experimenting with newer and better ways to obtain such effects. 
POV-Ray lends itself to the spirit of investigation and experimentation. 
  You can monitor this spirit on the POV newsgroups.  Ultimately, this 
leads to greater originality and scope in the artwork produced.  After 
woorking with POV for four years I still find that experts on the server 
are working with effects whose refinement I can barely perceive, let 
alone understand and accomplish myself.

Virtualight seems to be trying to integrate with Maya.  This is a 
different niche from the one POV occupies.  However, if it supports a 
Scene Description Language similar to POV's, maybe its not so different.

I recently began investigating freeware raytracers in order to recommend
something to a neighbour who was getting interested in 3d cg.  He plans 
to attend an art college in the fall where he will presumably be 
introduced to some sort of commercial software.  But how to develop his 
interest in the meantime?  I readily recommended Wings 3D to him as a 
very usable mesh modeller with a shallow learning curve, and the added 
advantage the its interface mimicks that of a commercial product.  But 
when it came to finding a renderer with similar features, I was not so 
successful.  Virtualight was knocked out because it seems only to be 
available for Windows.  He has a Mac.  Art of Illusion seemed less than 
robust.  3Delight is renderman compliant so might be a way to go except 
for the steep learning curve.  POV is more accessible but its SDL is 
arcane relative to the commercial world. Blender by reputation is also 
arcane. Lightray3D might be the solution, I have to test it further.  In 
the meantime I have him doing his rendering in Bryce which he was 
introduced to in HS.  I am hoping Bryce's materials lab is similar 
enough in its metaphor to texturing in other commercial packages.  But I 
don't think Bryce 4 supports uv mapping.

So that got a bit longwinded but in summary, if your interest is 
freeware, and basically amateur in its goals, I would recommend POV over 
Virtualight unreservedly. You will become very skilled indeed before you 
"outgrow" it, and the community of other users is a rich resource. But 
the knowledge you gain that can be ported to the commercial world is 
relatively general.  If you are trying to accumulate knowledge toward a 
commercial career, you may need to be more crafty in the software you 
choose to learn.

-Jim

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hey daniel


> There seems be different pov file for each objects.
> Does complex scene normally built from rendering objects
>separately and then piece them together or am I getting
> really confuse here?

No, splitting up the code into several files makes it easier for you to
organize your scene. You keep one main scene file and include all your
object-files in there. A little example:

//This goes into "myobject.inc"
#declare MyObject = {
    //Your nice little object goes here
}

//Your main scene file:

#include "myobject.inc"
/*
makes the content of the file myobject.inc available
in your main scene file
*/

object {
    MyObject
    //translate & rotate stuff
}

This way it's possible for you to have a pretty small main scene file that
is still manageable. And it's much easier for you to use an object from a
former scene in a new one. You could easily write in another scene #include
"myobject.inc" and you would have your object again...

The image is still rendered as a whole. So the whole thing is really just to
make your life much easier ;-)

hth,
Florian

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On Sat, 24 May 2003 05:08:48 +1200, "Daniel Ngu" <ngu### [at] xtraconz> wrote:
> "Hugo Asm" <hua### [at] post3teledk> wrote:
> > Some features may be readily available in Virtual Light, but when you get to
> > know POV-Ray, there are a lot of "plugins" that I think it will turn around
> > the picture for you. They are usually called "include files" or "macros".
>
> Can you please recommend a good source

http://www.f-lohmueller.de/
http://www.povworld.org/
http://www.povray.org/resources/
http://www.oyonale.com/ressources/english/index.htm
http://www.google.org/ (if necessary)

> for large collection of plugins?

Do not follow this name. I'm sure Hugo used "plugin" term to refer to
possibilities available in other applications. But in fact include files and
macros are parts of scenes - just subsections from there shared between users.

> SkyLight (int samples, rgbexpr color, float brightness) where:
> samples: the number of ray samples to cast at each intersection point in
> order to estimate irradiance; and

So is it just set of shadowless point light sources ?

> SunLight (int hours : int minutes, int samples, float brightness, rgb color)

http://www.povray.org/documentation/view/291/#sunpos
http://www.chris-dennis.ndtilda.co.uk/suninc.html
http://www.oyonale.com/ressources/english/sources13.htm

The adventage of POV is that you are not limited to founded solutions, but
having include files you can choose something which fits your needs best, and
then you can modify it yourself to fit better.

ABX

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3ece50b1@news.povray.org...
> It is absolutely gorgeous.
Thanks!
> There seems be
> different pov file for each objects.  Does complex scene normally built
from
> rendering objects separately and then piece them together or am I getting
> really confuse here?

In addition to what Florian said, there are in fact different ways to deal
with complex scenes, but basically it all comes down to being able to test
your scene and individual objects with a minimum effort. For instance,
objects like large meshes can be simply too big to be handled in a scene
file. Keeping an object in its own file also allows to test and tweak it
separately, and makes it easily reusable. For instance, I have a 180 Mb
bicycle+biker mesh that I can now just plug in in any scene I want. Ditto
for trees, grass etc.
Some people tend to have a very short master file calling all the main items
from textures to objects. I used to do that, but I now tend to have a rather
long master scene (1000-2000 lines) calling only the biggest (in terms of
file size) objects and their textures. Keeping the file well structured is
of course mandatory.

G.

--

**********************
http://www.oyonale.com
**********************
- Graphic experiments
- POV-Ray and Poser computer images
- Posters

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Daniel wrote:
> "skylight is treated as a large hemispherical direct light
> source at infinity also named sky dome. It completely
> surrounds the world and doesn't cast any shadow."

ABX wrote:
> So is it just a set of shadowless point light sources ?

I think it just means the skydome does not cast a big shadow over the entire
world. In POV-Ray it's called a "sky sphere" and it probably works the same
way when you activate radiosity. Here's a little example; try toggling the
on/off switches and see the differences:


// Needs POV-Ray 3.5
camera { location <-5,2,-10> look_at <0,-1,-1> }

// Objects
#default { finish { ambient 0 brilliance 1.5 } }
plane  {  y,-3        pigment { rgb <.6,.55,.45> } }
box    { -3, <3,-1,3> pigment { rgb <.8,.75,.65> } }
sphere {  0,1         pigment { rgb 1 } }


// Switch on / off light elements
#declare Radiosity = on;
#declare Sky_Sphere = on;
#declare Light_Source = on;


#if (Radiosity = on)
    #include "rad_def.inc"
    global_settings { assumed_gamma 1.5 radiosity {
        Rad_Settings(Radiosity_Fast, off, off) brightness 1.6 }
 }
#end

#if (Sky_Sphere = on)
 sky_sphere { pigment {
     gradient y pigment_map {
         [  0  rgb <.5,1,2> ]
         [ .5  rgb <.1,.4,1> ] }
     }
 }
#end

#if (Light_Source = on)
    light_source { <-1000,1000,500>, 1.3
        area_light x*150,y*150, 3,3 adaptive 1 circular orient
    }
#end

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