POV-Ray : Newsgroups : povray.general : shadow problem Server Time
29 Jul 2024 02:30:47 EDT (-0400)
  shadow problem (Message 1 to 6 of 6)  
From: rodv92
Subject: shadow problem
Date: 20 Sep 2013 18:05:02
Message: <web.523cc64a476ca3b65d50475e0@news.povray.org>
hello group. I hope you can help me.

i have a fairly complex scene using lightsysIVc and one sun (light source)
i use no radiosity
i use ambient_light 0.5
i use #version 3.7
i replaced ambient with emission on some objects

the problem is objects where shadows are cast on, do not display any fine
texture details anymore on the cast shadow side. they appear as completely
uniform matte pigments.

More problematic, i tried to use no_shadow to get around the issue.
Does not work, shadow is still cast ! (i applied no_shadow to the object, then
inside the first level CSG, then on all last level objects of the nested CSG, no
effect)

something seems broken. please advise.


Post a reply to this message

From: Warp
Subject: Re: shadow problem
Date: 20 Sep 2013 18:56:54
Message: <523cd2b5@news.povray.org>
rodv92 <nomail@nomail> wrote:
> the problem is objects where shadows are cast on, do not display any fine
> texture details anymore on the cast shadow side. they appear as completely
> uniform matte pigments.

If you are using 'normal' statements in your textures, they work only
with direct lighting and radiosity (if normals are enabled in radiosity
calculations.)

If you don't want to either add finer geometry to the scene nor use
radiosity (which can admittedly be both really hard to set up right
and make rendering times enormously longer), try using some secondary
"fill light" sources (dimmer, perhaps a bit colored lights at places
where light would naturally "reflect" from major surfaces towards the
visible parts of your scene.) Not a perfect solution, but works ok when
well used.

-- 
                                                          - Warp


Post a reply to this message

From: Alain
Subject: Re: shadow problem
Date: 21 Sep 2013 15:11:29
Message: <523def61$1@news.povray.org>

> hello group. I hope you can help me.
>
> i have a fairly complex scene using lightsysIVc and one sun (light source)
> i use no radiosity
> i use ambient_light 0.5
> i use #version 3.7
> i replaced ambient with emission on some objects
>
> the problem is objects where shadows are cast on, do not display any fine
> texture details anymore on the cast shadow side. they appear as completely
> uniform matte pigments.
>
> More problematic, i tried to use no_shadow to get around the issue.
> Does not work, shadow is still cast ! (i applied no_shadow to the object, then
> inside the first level CSG, then on all last level objects of the nested CSG, no
> effect)
>
> something seems broken. please advise.
>
>
>

Ambient totaly negate your normals where it's the only source of 
illumination.

I'd turn down ambient down to a more "normal" value of around 0.1 or less.
Add a shadowless light located in the same location as the main light.
Reduce the intensity of the main light to keep the same overall 
illumination.

The shadowless light will bring out the effect of the normal from your 
textures.


Post a reply to this message

From: Jaime Vives Piqueres
Subject: Re: shadow problem
Date: 22 Sep 2013 03:09:31
Message: <523e97ab$1@news.povray.org>

> hello group. I hope you can help me.
>
> i have a fairly complex scene using lightsysIVc and one sun (light source)
> i use no radiosity
> i use ambient_light 0.5
> i use #version 3.7
> i replaced ambient with emission on some objects
>
> the problem is objects where shadows are cast on, do not display any fine
> texture details anymore on the cast shadow side. they appear as completely
> uniform matte pigments.
>
> More problematic, i tried to use no_shadow to get around the issue.
> Does not work, shadow is still cast ! (i applied no_shadow to the object, then
> inside the first level CSG, then on all last level objects of the nested CSG, no
> effect)
>
> something seems broken. please advise.

   Seems Warp and Alain didn't get to the real issue... are you using 
the no_shadow modifier on the object casting the shadow? (placing it on 
the object receiving the shadow will not work).

   Regards,

--
Jaime


Post a reply to this message

From: Alain
Subject: Re: shadow problem
Date: 23 Sep 2013 00:41:24
Message: <523fc674$1@news.povray.org>


>> hello group. I hope you can help me.
>>
>> i have a fairly complex scene using lightsysIVc and one sun (light
>> source)
>> i use no radiosity
>> i use ambient_light 0.5
>> i use #version 3.7
>> i replaced ambient with emission on some objects
>>
>> the problem is objects where shadows are cast on, do not display any fine
>> texture details anymore on the cast shadow side. they appear as
>> completely
>> uniform matte pigments.
This is the isue.

>>
>> More problematic, i tried to use no_shadow to get around the issue.
>> Does not work, shadow is still cast ! (i applied no_shadow to the
>> object, then
>> inside the first level CSG, then on all last level objects of the
>> nested CSG, no
>> effect)
This is an attempted workaround mis-using an unrelated feature.

>>
>> something seems broken. please advise.
>
>    Seems Warp and Alain didn't get to the real issue... are you using
> the no_shadow modifier on the object casting the shadow? (placing it on
> the object receiving the shadow will not work).
>
>    Regards,
>
> --
> Jaime

Using no_shadow was an attempt to get details in the shadowed area as a 
workaround.

The original isue is "no detail in the shadowed area".


Post a reply to this message

From: rodv92
Subject: Re: shadow problem
Date: 30 Sep 2013 17:50:00
Message: <web.5249f0ff6a1328145d50475e0@news.povray.org>
Alain <kua### [at] videotronca> wrote:


> >> hello group. I hope you can help me.
> >>
> >> i have a fairly complex scene using lightsysIVc and one sun (light
> >> source)
> >> i use no radiosity
> >> i use ambient_light 0.5
> >> i use #version 3.7
> >> i replaced ambient with emission on some objects
> >>
> >> the problem is objects where shadows are cast on, do not display any fine
> >> texture details anymore on the cast shadow side. they appear as
> >> completely
> >> uniform matte pigments.
> This is the isue.
>
> >>
> >> More problematic, i tried to use no_shadow to get around the issue.
> >> Does not work, shadow is still cast ! (i applied no_shadow to the
> >> object, then
> >> inside the first level CSG, then on all last level objects of the
> >> nested CSG, no
> >> effect)
> This is an attempted workaround mis-using an unrelated feature.
>
> >>
> >> something seems broken. please advise.
> >
> >    Seems Warp and Alain didn't get to the real issue... are you using
> > the no_shadow modifier on the object casting the shadow? (placing it on
> > the object receiving the shadow will not work).
> >
> >    Regards,
> >
> > --
> > Jaime
>
> Using no_shadow was an attempt to get details in the shadowed area as a
> workaround.
>
> The original isue is "no detail in the shadowed area".


Hello, thanks for all your responses. indeed there is a normal texture
simulating concrete, so i understand that i will lose detail.

And finally, I managed to appply no_shadow to the CSG, my bad ! : there was a
difference lingering in the code with only one object that i managed not to see.
i removed the offending difference and now everything is ok (no_shadow works
again !)

thank you !


Post a reply to this message

Copyright 2003-2023 Persistence of Vision Raytracer Pty. Ltd.