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From: [GDS|Entropy]
Subject: Re: RockTest.pov reference image
Date: 13 Dec 2016 17:20:01
Message: <web.5850736067b6c8b61c3f31c90@news.povray.org>
Alain <kua### [at] videotronca> wrote:

> > "Cousin Ricky" <rickysttATyahooDOTcom> wrote:
> >> "[GDS|Entropy]" <nomail@nomail> wrote:
> >>> Here is an "angry" media sky output from the Sky macro.
> >>
> >> Cecil B. DeMille worthy!
> >
> > Thank you. :)
> >
> > My goal is to build a fairly comprehensive "Environmentals" macro set that is
> > both simple to use and nice looking. Given that they are designed to work
> > together it should take a LOT of the work out of creating natural scenes, and
> > hopefully inspire some scenes.
> >
> > The Rocks macro is coming close to completion, for version 1 at least, and the
> > Terrain macro is close behind it. Next in the set is the Skies and Fogs.
> >
> > The Fog is being a little weird, because Media without a container is only
> > visible when looking at the plane below it, and it vanishes above the horizon.
> > ?! Weeeird. Very counterintuitive.
> >
> > Any idea why this is, and how to fix it? Is the only choice to bound the media?
> > I am guessing that this is because it is not reasonable to calculate media for
> > an infinite space, but I could be wrong.
> >
>
> You are correct on this point. Media sampling can only be computed
> between two deffined points. When you reatch the background, the far
> point is undefined, making the computation impossible.
>
> Solution : Place a background plane behond the scene. Make it no_image,
> no_shadow, no_refection and no_radiosity.
>
>
> Alain

When I tried that, the media disappeared entirely, here is the plane I used:

plane
{
    z,
    100
    no_radiosity
    no_image
    no_shadow
    no_reflection
}

Did I miss something?

Thanks!

Ian


Post a reply to this message

From: Alain
Subject: Re: RockTest.pov reference image
Date: 13 Dec 2016 17:51:20
Message: <58507b68$1@news.povray.org>

> Alain <kua### [at] videotronca> wrote:

>>> "Cousin Ricky" <rickysttATyahooDOTcom> wrote:
>>>> "[GDS|Entropy]" <nomail@nomail> wrote:
>>>>> Here is an "angry" media sky output from the Sky macro.
>>>>
>>>> Cecil B. DeMille worthy!
>>>
>>> Thank you. :)
>>>
>>> My goal is to build a fairly comprehensive "Environmentals" macro set that is
>>> both simple to use and nice looking. Given that they are designed to work
>>> together it should take a LOT of the work out of creating natural scenes, and
>>> hopefully inspire some scenes.
>>>
>>> The Rocks macro is coming close to completion, for version 1 at least, and the
>>> Terrain macro is close behind it. Next in the set is the Skies and Fogs.
>>>
>>> The Fog is being a little weird, because Media without a container is only
>>> visible when looking at the plane below it, and it vanishes above the horizon.
>>> ?! Weeeird. Very counterintuitive.
>>>
>>> Any idea why this is, and how to fix it? Is the only choice to bound the media?
>>> I am guessing that this is because it is not reasonable to calculate media for
>>> an infinite space, but I could be wrong.
>>>
>>
>> You are correct on this point. Media sampling can only be computed
>> between two deffined points. When you reatch the background, the far
>> point is undefined, making the computation impossible.
>>
>> Solution : Place a background plane behond the scene. Make it no_image,
>> no_shadow, no_refection and no_radiosity.
>>
>>
>> Alain
>
> When I tried that, the media disappeared entirely, here is the plane I used:
>
> plane
> {
>     z,
>     100
>     no_radiosity
>     no_image
>     no_shadow
>     no_reflection
> }
>
> Did I miss something?
>
> Thanks!
>
> Ian
>
>
Your plane is facing away from the camera, placing the camera /inside/ 
the plane.

Add hollow to your plane or reverse it's normal and offset.

plane{
  -z, -100 // Makes the plane face the camera
  no_radiosity no_image no_shadow no_reflection
}

OR

plane{
  z, 100
  no_radiosity no_image no_shadow no_reflection
  hollow // allow media to exist "inside" the plane
}

You could also use inverse instead of hollow or revercing the plane 
orientation.


Alain


Post a reply to this message

From: [GDS|Entropy]
Subject: Re: RockTest.pov reference image
Date: 13 Dec 2016 18:10:01
Message: <web.58507ecf67b6c8b61c3f31c90@news.povray.org>
Alain <kua### [at] videotronca> wrote:

> > Alain <kua### [at] videotronca> wrote:

> >>> "Cousin Ricky" <rickysttATyahooDOTcom> wrote:
> >>>> "[GDS|Entropy]" <nomail@nomail> wrote:
> >>>>> Here is an "angry" media sky output from the Sky macro.
> >>>>
> >>>> Cecil B. DeMille worthy!
> >>>
> >>> Thank you. :)
> >>>
> >>> My goal is to build a fairly comprehensive "Environmentals" macro set that is
> >>> both simple to use and nice looking. Given that they are designed to work
> >>> together it should take a LOT of the work out of creating natural scenes, and
> >>> hopefully inspire some scenes.
> >>>
> >>> The Rocks macro is coming close to completion, for version 1 at least, and the
> >>> Terrain macro is close behind it. Next in the set is the Skies and Fogs.
> >>>
> >>> The Fog is being a little weird, because Media without a container is only
> >>> visible when looking at the plane below it, and it vanishes above the horizon.
> >>> ?! Weeeird. Very counterintuitive.
> >>>
> >>> Any idea why this is, and how to fix it? Is the only choice to bound the media?
> >>> I am guessing that this is because it is not reasonable to calculate media for
> >>> an infinite space, but I could be wrong.
> >>>
> >>
> >> You are correct on this point. Media sampling can only be computed
> >> between two deffined points. When you reatch the background, the far
> >> point is undefined, making the computation impossible.
> >>
> >> Solution : Place a background plane behond the scene. Make it no_image,
> >> no_shadow, no_refection and no_radiosity.
> >>
> >>
> >> Alain
> >
> > When I tried that, the media disappeared entirely, here is the plane I used:
> >
> > plane
> > {
> >     z,
> >     100
> >     no_radiosity
> >     no_image
> >     no_shadow
> >     no_reflection
> > }
> >
> > Did I miss something?
> >
> > Thanks!
> >
> > Ian
> >
> >
> Your plane is facing away from the camera, placing the camera /inside/
> the plane.
>
> Add hollow to your plane or reverse it's normal and offset.
>
> plane{
>   -z, -100 // Makes the plane face the camera
>   no_radiosity no_image no_shadow no_reflection
> }
>
> OR
>
> plane{
>   z, 100
>   no_radiosity no_image no_shadow no_reflection
>   hollow // allow media to exist "inside" the plane
> }
>
> You could also use inverse instead of hollow or revercing the plane
> orientation.
>
>
> Alain

That does make the media reappear [using either inverse or hollow], but also
retains the issue of the media vanishing above horizon. I must really be borking
this up lol! :)

Ian


Post a reply to this message

From: clipka
Subject: Re: RockTest.pov reference image
Date: 13 Dec 2016 19:14:50
Message: <58508efa$1@news.povray.org>
Am 13.12.2016 um 22:15 schrieb [GDS|Entropy]:

> The Fog is being a little weird, because Media without a container is only
> visible when looking at the plane below it, and it vanishes above the horizon.
> ?! Weeeird. Very counterintuitive.

Doesn't sound like something that should happen.

Care to share any details?


Post a reply to this message

From: [GDS|Entropy]
Subject: Re: RockTest.pov reference image
Date: 13 Dec 2016 21:35:00
Message: <web.5850afb167b6c8b61c3f31c90@news.povray.org>
clipka <ano### [at] anonymousorg> wrote:
> Am 13.12.2016 um 22:15 schrieb [GDS|Entropy]:
>
> > The Fog is being a little weird, because Media without a container is only
> > visible when looking at the plane below it, and it vanishes above the horizon.
> > ?! Weeeird. Very counterintuitive.
>
> Doesn't sound like something that should happen.
>
> Care to share any details?

Sure. :)

The plane in there seems to have no effect, commented or no, which seems to be
improper based on what Alain was saying. Here is a minimal scene which
reproduces the effect being discussed.

#include "functions.inc"

#macro RRand(RS, Min, Max)
    (rand(RS) * (Max - Min) + Min)
#end

#declare Radiosity = true;
#declare AreaLight = true;

#declare globalFogActive = true;
#declare globalFogDensity = true;
#declare globalFogBaseValue = 0.1;

#local ScaleAmount = 120.0;   //    Was 60.
#local ScaleFactor = ScaleAmount / ((ScaleAmount * 2.50) * (log(ScaleAmount)));

#local ColorFactor = (((ScaleAmount * ScaleFactor) / (ScaleAmount)) /
(ScaleFactor * ScaleFactor));

global_settings
{
    assumed_gamma 1.0
    //max_trace_level 25
    #if (Radiosity)
        radiosity
        {
            pretrace_start      0.08    //    start pretrace at this size
            pretrace_end        0.04    //    end pretrace at this size
            count               35      //    higher -> higher quality (1..1600)
[35]
            nearest_count       5       //    higher -> higher quality (1..10)
[5]
            error_bound         2.8     //    higher -> smoother, less accurate
[1.8]
            recursion_limit     6       //    how much interreflections are
calculated (1..5+) [3]
            low_error_factor    0.5     //    reduce error_bound during last
pretrace step
            gray_threshold      0.0     //    increase for weakening colors
(0..1) [0]
            minimum_reuse       0.015   //    reuse of old radiosity samples
[0.015]
            brightness          1       //    brightness of radiosity effects
(0..1) [1]

            adc_bailout         0.01 / 2
            //normal on                 //    take surface normals into account
[off]
            media on                    //    take media into account [off]
            //save_file "file_name"     //    save radiosity data
            //load_file "file_name"     //    load saved radiosity data
            //always_sample off           //    turn sampling in final trace off
[on]
            always_sample on
            //max_sample 1.0            //    maximum brightness of samples
        }
    #end
}

#default
{
    texture
    {
        pigment
        {
            rgb 1
        }

        #if (Radiosity)
            finish
            {
                ambient 0.0
                diffuse 0.6
                specular 0.3
            }
        #else
            finish
            {
                ambient 0.1
                diffuse 0.6
                specular 0.3
            }
        #end
    }
}

#if (AreaLight)
    light_source
    {
        0 * x
        color rgb <0.2734, 0.5078, 0.7031>
        area_light
        <100, 0, 0>
        <0, 0, 100>
        4, 4
        adaptive 0
        jitter
        translate <0,1000,-2000>
        photons
        {
            refraction on
            reflection on
        }
    }
#else
    light_source
    {
        0 * x
        color rgb <1, 1, 1>
        translate <-20, 40, -20>
        photons
        {
            refraction on
            reflection on
        }
    }
#end

        camera
        {
         location <-5, 6, -18>
         up y * image_height
         right x * image_width
         look_at <0, 1.5, 0>
         angle 45
        }

plane
{
    z,
    100
    no_radiosity
    no_image
    no_shadow
    no_reflection
    inverse
}

//    Global media.
#macro GlobalFog(base, useDensity)

    #if (useDensity)

        media
        {
            method 3
            //samples 10, 100
            samples 1, 10

            scattering
            {
                1, <1, 1, 1> * 0.01
            }

            intervals 15

            density
            {
                //granite   //    Very wispy.
                bumps     //    Smooth, evenly changing density.

                #if (ScaleAmount > 15)
                    scale 1 / ScaleAmount
                #end

                color_map
                {
                    #local Kk = 0;

                    #while(Kk <= 10)
                        #if (Kk = 0)
                            [Kk * 0.1 rgb <Kk, Kk, Kk>]
                        #else
                            [Kk * 0.1 rgb <Kk, Kk, Kk> * (base + 0.1) /
ScaleFactor]
                        #end
                    #local Kk = Kk + 1;
                    #end

                    #while(Kk >= 10)
                        #if (Kk = 0)
                            [Kk * 0.1 rgb <Kk, Kk, Kk>]
                        #else
                            [Kk * 0.1 rgb <Kk, Kk, Kk> * (base + 0.0) /
ScaleFactor]
                        #end
                    #local Kk = Kk - 1;
                    #end
                }

                turbulence 0.25
            }
        }
    #else
        media
        {
            method 3
            //samples 10, 100
            samples 1, 10

            scattering
            {
                1, <1, 1, 1> * 0.01
            }

            intervals 15
        }
    #end
#end

#if (globalFogActive)
    GlobalFog(globalFogBaseValue, globalFogDensity)
#end

#declare f_Height =
function
{
    0.5 * f_wrinkles(x * 0.4, y * 0.4, z * 0.4)
}

#macro Ground(Height, Extent)
    #local eX = Extent.x;
    #local eY = Extent.y;
    #local eZ = Extent.z;

    #local GroundSurface =
    isosurface
    {
        function
        {
            //(y - f_Height(x, -1, z)) / Height
            (y - (0.5 * f_wrinkles(x * eX, y * eY, z * eZ))) / Height
        }

        max_gradient 2.0

        contained_by
        {
            box
            {
                <-400, -5, -400>,
                <400, 0.15, 400>
            }
        }

        accuracy 1e-3
    }

    object
    {
        GroundSurface
    }
#end

#local GroundExtent = <0.4, 0.4, 0.4>;
Ground(10.6, GroundExtent)

#macro DistributePoles(Extent, CameraLocation)
    #local RsA = seed(112080);

    #local Poles =
    union
    {
        #local I = -Extent;
        #while(I < Extent)
            #local J = -Extent;
            #while(J < Extent)

                cylinder
                {
                    <I, 0, J> * 2,
                    <I, 1, J> * 2,
                    0.25

                }

            #local J = J + 1;
            #end
        #local I = I + 1;
        #end
    }

    object
    {
        Poles
        translate <Extent * 0.5, 0, Extent * 0.5>
    }
#end

#local Extent = 20;
DistributePoles(Extent, <0, 10, -10>)


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From: omniverse
Subject: Re: RockTest.pov reference image
Date: 14 Dec 2016 00:10:00
Message: <web.5850d3a067b6c8b69c5d6c810@news.povray.org>
"[GDS|Entropy]" <nomail@nomail> wrote:
> clipka <ano### [at] anonymousorg> wrote:
> > Am 13.12.2016 um 22:15 schrieb [GDS|Entropy]:
> >
> > > The Fog is being a little weird, because Media without a container is only
> > > visible when looking at the plane below it, and it vanishes above the horizon.
> > > ?! Weeeird. Very counterintuitive.
> >
> > Doesn't sound like something that should happen.
> >
> > Care to share any details?
>
> Sure. :)
>
> The plane in there seems to have no effect, commented or no, which seems to be
> improper based on what Alain was saying. Here is a minimal scene which
> reproduces the effect being discussed.

'Official' and 'alpha' versions render differently so something changed, I guess
you're not using official 3.7? I get the black void in 3.7.1.1-alpha, while
official 3.7.0 shows oversaturation of media as would be expected.

If you add the following spotlight to your (1st) light, it can apparently create
a finite region for the rays. That is mentioned in the docs:

http://wiki.povray.org/content/Reference:Atmospheric_Media

  spotlight point_at <0,-1,1> radius 18 falloff 20

This could take some tweaking to get better, I just threw it in there, but there
didn't seem to be much range beyond that radius and falloff before it fails to
look okay again. Maybe with better point_at angle, just so it isn't directed
into infinity again.

Bob


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From: [GDS|Entropy]
Subject: Re: RockTest.pov reference image
Date: 14 Dec 2016 00:30:00
Message: <web.5850d83e67b6c8b61c3f31c90@news.povray.org>
"omniverse" <omn### [at] charternet> wrote:
> "[GDS|Entropy]" <nomail@nomail> wrote:
> > clipka <ano### [at] anonymousorg> wrote:
> > > Am 13.12.2016 um 22:15 schrieb [GDS|Entropy]:
> > >
> > > > The Fog is being a little weird, because Media without a container is only
> > > > visible when looking at the plane below it, and it vanishes above the horizon.
> > > > ?! Weeeird. Very counterintuitive.
> > >
> > > Doesn't sound like something that should happen.
> > >
> > > Care to share any details?
> >
> > Sure. :)
> >
> > The plane in there seems to have no effect, commented or no, which seems to be
> > improper based on what Alain was saying. Here is a minimal scene which
> > reproduces the effect being discussed.
>
> 'Official' and 'alpha' versions render differently so something changed, I guess
> you're not using official 3.7? I get the black void in 3.7.1.1-alpha, while
> official 3.7.0 shows oversaturation of media as would be expected.
>
> If you add the following spotlight to your (1st) light, it can apparently create
> a finite region for the rays. That is mentioned in the docs:
>
> http://wiki.povray.org/content/Reference:Atmospheric_Media
>
>   spotlight point_at <0,-1,1> radius 18 falloff 20
>
> This could take some tweaking to get better, I just threw it in there, but there
> didn't seem to be much range beyond that radius and falloff before it fails to
> look okay again. Maybe with better point_at angle, just so it isn't directed
> into infinity again.
>
> Bob

You are correct I am using UberPov, but didn't think to include that information
because I had seen this before [above horizon cutoff] in other versions of Pov.

Ian


Post a reply to this message

From: clipka
Subject: Re: RockTest.pov reference image
Date: 14 Dec 2016 00:44:32
Message: <5850dc40$1@news.povray.org>
Am 14.12.2016 um 06:07 schrieb omniverse:
> "[GDS|Entropy]" <nomail@nomail> wrote:
>> clipka <ano### [at] anonymousorg> wrote:
>>> Am 13.12.2016 um 22:15 schrieb [GDS|Entropy]:
>>>
>>>> The Fog is being a little weird, because Media without a container is only
>>>> visible when looking at the plane below it, and it vanishes above the horizon.
>>>> ?! Weeeird. Very counterintuitive.
>>>
>>> Doesn't sound like something that should happen.
>>>
>>> Care to share any details?
>>
>> Sure. :)
>>
>> The plane in there seems to have no effect, commented or no, which seems to be
>> improper based on what Alain was saying. Here is a minimal scene which
>> reproduces the effect being discussed.
> 
> 'Official' and 'alpha' versions render differently so something changed, I guess
> you're not using official 3.7? I get the black void in 3.7.1.1-alpha, while
> official 3.7.0 shows oversaturation of media as would be expected.

Actually, no, that's not what is happening.

Official 3.7.0 shows oversaturation simply because media sampling method
3 had always been buggy, showing somewhat wrong results wherever the
actual number of samples is low (such as in uniform media); this has
been fixed in 3.7.1.

With media sampling methods 1 and 2, POV-Ray has always (since 3.6.2 at
any rate) shown the very same symptoms.

To demonstrate that 3.7.0 sampling method 3 behavior /cannot/ be
correct, just notice how the oversaturation disappears close to the
horizon. With proper computations we should expect exactly the opposite
effect.


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From: Jérôme M. Berger
Subject: Re: RockTest.pov reference image
Date: 14 Dec 2016 01:18:06
Message: <5850e41e$1@news.povray.org>
On 12/14/2016 12:05 AM, [GDS|Entropy] wrote:
> That does make the media reappear [using either inverse or hollow], but
 also
> retains the issue of the media vanishing above horizon. I must really b
e borking
> this up lol! :)
> 
	Don't make the plane no_image no_reflection, and instead make it fully
transparent (rgbt 1).

		Jerome
-- 
mailto:jeb### [at] freefr
http://jeberger.free.fr
Jabber: jeb### [at] jabberfr


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From: omniverse
Subject: Re: RockTest.pov reference image
Date: 14 Dec 2016 02:35:01
Message: <web.5850f58967b6c8b69c5d6c810@news.povray.org>
=?UTF-8?B?SsOpcsO0bWUgTS4gQmVyZ2Vy?= <jeberger@free.fr> wrote:
> On 12/14/2016 12:05 AM, [GDS|Entropy] wrote:
> > That does make the media reappear [using either inverse or hollow], but
>  also
> > retains the issue of the media vanishing above horizon. I must really b
> e borking
> > this up lol! :)
> >
>  Don't make the plane no_image no_reflection, and instead make it fully
> transparent (rgbt 1).

Must be the no_image. I tried doing that, pigment {rgbt 1}, and it isn't needed
either.

Thanks Clipka for the media 3 explanation.


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