POV-Ray : Newsgroups : povray.newusers : "Fade away" overlay for existing objects Server Time
31 Oct 2024 19:42:34 EDT (-0400)
  "Fade away" overlay for existing objects (Message 1 to 10 of 10)  
From: severedo
Subject: "Fade away" overlay for existing objects
Date: 23 Jun 2015 14:45:00
Message: <web.5589a875d9d19c39f3d9f53f0@news.povray.org>
I have a finished scene made out of different objects.
Now I want to focus on the middle of this scene, for this I would like to have a
particular area (such as a simple circle) sharp and unperturbed and with
increasing radius I want the rest of the scene to gently fade away into the
blank white background. The fading should look like this just in a circular
manner
starting from the center of the image:

https://www.flickr.com/photos/portier/3969225787

I tried to put a torus around the part of the scene that I want to focus on
and make it transparent or White but it does not
really work and the "White" of the torus is also not really mixing with the
white
background, this is probably due to some shadow effects. I'm sure there must be
a simple solution for this... Thanks for your help!


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From: severedo
Subject: Re: "Fade away" overlay for existing objects
Date: 23 Jun 2015 16:15:00
Message: <web.5589be2c7840cf75f3d9f53f0@news.povray.org>
In the meantime i stumbled upon the fog feature. It does exactly what I want
except that I can only define a plane but not really another geometry:

 fog{ fog_type 2
      distance  3
      color     White
      fog_offset -5.5
      fog_alt    2.0
      turbulence 1.8
      up <-0.5,1,0>
    }

This would be great if I could somehow define a center point where the fog
then starts expanding like a sphere, obscuring everything.


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From: Alain
Subject: Re: "Fade away" overlay for existing objects
Date: 23 Jun 2015 17:05:40
Message: <5589ca24@news.povray.org>

> In the meantime i stumbled upon the fog feature. It does exactly what I want
> except that I can only define a plane but not really another geometry:
>
>   fog{ fog_type 2
>        distance  3
>        color     White
>        fog_offset -5.5
>        fog_alt    2.0
>        turbulence 1.8
>        up <-0.5,1,0>
>      }
>
> This would be great if I could somehow define a center point where the fog
> then starts expanding like a sphere, obscuring everything.
>
>

If you want sometning circular, the disk may be what you need:
disk{<0,0,0>, <0,0,-1>, 1 pigment{spherical colour_map{[0 rgb 
background_colour][clock background_colour filter 1] } scale Some_Scale 
translate Somewhere hollow}
If your scene use any media or fog, the hollow is needed it you want the 
media or fog to act predictably. A disk have an interior that is the 
same as that of a plane and it's not limited to the visible part.
You may also use a plane similarly.

This, in an animation, will start with a totaly transparent disk that 
will become increasingly opaque in a circular gradient. The center will 
stay transparent. Using the background's colour and manipulating the 
filter component ensure that the mix will be concistent.

Another way would be with some media. The density of a media can be 
exactly controled by a pigment of any function. The spherical pattern 
start with a value of zero at the origin and drop to zero at a radius of 
1. This can be changed by using a colour_map and an alternate wave type 
for the way it changes, and by scaling to adjust it to your needs.



Alain


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From: clipka
Subject: Re: "Fade away" overlay for existing objects
Date: 23 Jun 2015 17:19:43
Message: <5589cd6f$1@news.povray.org>
Am 23.06.2015 um 22:14 schrieb severedo:
> In the meantime i stumbled upon the fog feature. It does exactly what I want
> except that I can only define a plane but not really another geometry:
>
>   fog{ fog_type 2
>        distance  3
>        color     White
>        fog_offset -5.5
>        fog_alt    2.0
>        turbulence 1.8
>        up <-0.5,1,0>
>      }

Have you looked at media yet?


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From: William F Pokorny
Subject: Re: "Fade away" overlay for existing objects
Date: 23 Jun 2015 22:25:43
Message: <558a1527@news.povray.org>
On 06/23/2015 04:14 PM, severedo wrote:
> In the meantime i stumbled upon the fog feature. It does exactly what I want
> except that I can only define a plane but not really another geometry:
>
>   fog{ fog_type 2
>        distance  3
>        color     White
>        fog_offset -5.5
>        fog_alt    2.0
>        turbulence 1.8
>        up <-0.5,1,0>
>      }
>
> This would be great if I could somehow define a center point where the fog
> then starts expanding like a sphere, obscuring everything.
>
>
In addition to what has been suggested a couple other possible methods 
come to mind.

1) I've never done it, but with fog you are not limited to one use in a 
scene meaning you could declare a base fog and then instantiate several 
copies of it, rotating each variously around your "axis of clarity." Not 
sure what happens with the fog where the regions of fog overlap.

2) You could try the aoi pattern with a plane in front of the camera. I 
tried this myself just now with the code below. Simple tuning is 
possible by playing with the color map in the example, more complex 
foggy looks can be achieved by using the aoi pattern with more complex 
pigments/textures in a map. Whether enough to get the effect you really 
want not sure.

Good hunting.
Bill P.


//-------------------- fadeFromCenter.pov -----------------------
#version 3.7;
global_settings {
     assumed_gamma 1
     ambient_light srgb <1,1,1>
}
#declare Grey50 = srgbft <0.5,0.5,0.5,0,0>;
background { color Grey50 }
#declare CameraLocation = <4.50,4.50,-4.501>;
#declare CameraLookAt = <0.0,0.0,0.0>;
#declare Camera00 = camera {
     perspective
     location CameraLocation
     sky <0,1,0>
     angle 35
     right x*(image_width/image_height)
     look_at CameraLookAt
}
#declare White = srgbft <1,1,1,0,0>;
#declare Light00 = light_source { <50,150,-250>, White }
#declare Brown_Bramble = srgbft <0.349,0.1569,0.01569,0,0>;
#declare PlaneY = plane { <0,1,0>, 0
     pigment { color Brown_Bramble }
}
#include "transforms.inc"
#declare TransformToCam = transform {
     Reorient_Trans(<0.0,-1.0,0.0>,CameraLookAt-CameraLocation)
     translate CameraLocation
}
#declare PlaneCamera = plane { <0,1,0>, -1
     transform TransformToCam
}
#declare Red = srgbft <1,0,0,0,0>;
#declare CylinderX = cylinder {
     <-10,0,0>, <10,0,0>, 0.01
     pigment { color Red }
}
#declare Green = srgbft <0,1,0,0,0>;
#declare CylinderY = cylinder {
     <0,-10,0>, <0,10,0>, 0.01
     pigment { color Green }
}
#declare Blue = srgbft <0,0,1,0,0>;
#declare CylinderZ = cylinder {
     <0,0,-10>, <0,0,10>, 0.01
     pigment { color Blue }
}
#declare ColorImageCenter = srgbft <1,1,1,0,1>;
#declare ColorImageEdge = srgbft <1,1,1,0,0>;
#declare ColorMap_AOIfade = color_map {
     [ 0 ColorImageEdge ]
     [ 0.75 ColorImageEdge ]
     [ 0.975 ColorImageCenter ]
     [ 1 ColorImageCenter ]
}
#declare Pigment_AOIfade = pigment { aoi color_map { ColorMap_AOIfade }}
#declare Texture_AOIfade = texture { pigment { Pigment_AOIfade } }
#declare ObjCameraPlane = object {
     object { PlaneCamera }
     texture { Texture_AOIfade }
     hollow no_shadow
}
//---
camera { Camera00 }
light_source { Light00 }
object { CylinderX }
object { CylinderY }
object { CylinderZ }
object { PlaneY }
object { ObjCameraPlane }


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From: William F Pokorny
Subject: Re: "Fade away" overlay for existing objects
Date: 24 Jun 2015 05:04:07
Message: <558a7287$1@news.povray.org>
On 06/23/2015 10:25 PM, William F Pokorny wrote:
>
> //-------------------- fadeFromCenter.pov -----------------------
........
> #declare ObjCameraPlane = object {
>      object { PlaneCamera }
>      texture { Texture_AOIfade }
>      hollow no_shadow
> }
........
>
Woke up with the thought the plane in front of the camera should also 
have :

     no_reflection
     no_radiosity

to not cause side effects for scenes with reflection/radiosity.

Bill P.


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From: Stephen
Subject: Re: "Fade away" overlay for existing objects
Date: 24 Jun 2015 06:46:38
Message: <558a8a8e$1@news.povray.org>
On 24/06/2015 10:04, William F Pokorny wrote:
> Woke up with the thought the plane in front of the camera should also
> have :

You Know That You Have Been Raytracing To Long, when... :-P

-- 

Regards
     Stephen


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From: Alain
Subject: Re: "Fade away" overlay for existing objects
Date: 24 Jun 2015 12:28:46
Message: <558adabe@news.povray.org>

> On 06/23/2015 04:14 PM, severedo wrote:
>> In the meantime i stumbled upon the fog feature. It does exactly what
>> I want
>> except that I can only define a plane but not really another geometry:
>>
>>   fog{ fog_type 2
>>        distance  3
>>        color     White
>>        fog_offset -5.5
>>        fog_alt    2.0
>>        turbulence 1.8
>>        up <-0.5,1,0>
>>      }
>>
>> This would be great if I could somehow define a center point where the
>> fog
>> then starts expanding like a sphere, obscuring everything.
>>
>>
> In addition to what has been suggested a couple other possible methods
> come to mind.
>
> 1) I've never done it, but with fog you are not limited to one use in a
> scene meaning you could declare a base fog and then instantiate several
> copies of it, rotating each variously around your "axis of clarity." Not
> sure what happens with the fog where the regions of fog overlap.
>

When several fog overlap, their effects are added.


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From: Nekar Xenos
Subject: Re: "Fade away" overlay for existing objects
Date: 27 Jun 2015 12:05:01
Message: <web.558ec8e97840cf7550cbefc00@news.povray.org>
"severedo" <nomail@nomail> wrote:
> I have a finished scene made out of different objects.
> Now I want to focus on the middle of this scene, for this I would like to have a
> particular area (such as a simple circle) sharp and unperturbed and with
> increasing radius I want the rest of the scene to gently fade away into the
> blank white background. The fading should look like this just in a circular
> manner
> starting from the center of the image:
>
> https://www.flickr.com/photos/portier/3969225787
>
> I tried to put a torus around the part of the scene that I want to focus on
> and make it transparent or White but it does not
> really work and the "White" of the torus is also not really mixing with the
> white
> background, this is probably due to some shadow effects. I'm sure there must be
> a simple solution for this... Thanks for your help!

This sounds like media with a radial density map to me. Adding a little
turbulence will finish it off nicely.

-Nekar Xenos-


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From: Leroy
Subject: Re: "Fade away" overlay for existing objects
Date: 17 Jul 2015 13:45:57
Message: <55a93f55@news.povray.org>
Sorry for the very late reply. I haven't been here in awhile.

You probably already figure out what to use on this project.
But I have something that might help on other projects.

Why not use post production techniques with POV?
Use picture as an image_map pigment then use that pigment in a
pigment_map with other pigments. You could use any pattern to put them 
together as you like!

I've already made a system for animating fades for POV animations.
You can download it Here
http://leroywhetstone.s5.com/Pages/PovFiles.html#Tools


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