I am trying to create a texture in which selected parts, masked by an 
alpha mask in the image (png) will glow, even when little or no light is 
shining on the surface. Any sugestions ??

bit

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> I am trying to create a texture in which selected parts, masked by an 
> alpha mask in the image (png) will glow, even when little or no light is 
> shining on the surface. Any sugestions ??
> 
> bit

Any texture with a ambient >0 will glow by itself.
Just set the underlying texture with an ambient value like "ambient 1", 
and the mask with "ambient 0"
If your scene use radiosity, those parts will actualy illuminate ther 
surrounding, but NOT any media.


If you want a glowing hallo, you need to put some emissive media in the 
area.
In this case, you may use a blured, black and white, version of your 
mask and use it as a density_map for the media.
In a radiosity scene, that media can shed light IF you set "media on" in 
the radiosity clock.



Alain

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Alain wrote:

>> I am trying to create a texture in which selected parts, masked by an 
>> alpha mask in the image (png) will glow, even when little or no light 
>> is shining on the surface. Any sugestions ??
>>
>> bit
> 
> Any texture with a ambient >0 will glow by itself.
> Just set the underlying texture with an ambient value like "ambient 1", 
> and the mask with "ambient 0"
> If your scene use radiosity, those parts will actualy illuminate ther 
> surrounding, but NOT any media.

I tried that but pov objected. I tried with "ambient 1" in the texture 
itself, in the pigment, and in the image_map, and pov objects each time. 
where do i put the ambient ??

#declare my_texture = texture {
	pigment {
		image_map {
			png "my_image.png"
			map_type 1    // spherical
			interpolate 2 // bilinear
		}
	}
}

thanks

bit

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BitViper wrote:
> where do i put the ambient ??
> 
> #declare my_texture = texture {
>     pigment {
>         image_map {
>             png "my_image.png"
>             map_type 1    // spherical
>             interpolate 2 // bilinear
>         }
>     }
> }

Ambient goes in the "finish" block:

#declare my_texture =
texture {
   pigment {
     image_map {
       png "my_image.png"
       map_type 1
       interpolate 2
     }
   }
   finish {
     ambient 1
   }
}

Hope this helps!

--Sherry Shaw


-- 
#macro T(E,N)sphere{x,.4rotate z*E*60translate y*N pigment{wrinkles scale
.3}finish{ambient 1}}#end#local I=0;#while(I<5)T(I,1)T(1-I,-1)#local I=I+
1;#end camera{location-5*z}plane{z,37 pigment{granite color_map{[.7rgb 0]
[1rgb 1]}}finish{ambient 2}}//                                   TenMoons

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Sherry Shaw wrote:

> Ambient goes in the "finish" block:

Sweeeeeet! That did it. I forgot about the finish, have only used it 
twice in all of my playing with povray. Needless to say until now I 
havent gotten into the fancy things.

Here's the result.

http://www.bitviper.org/solarsystem/earth_lights.png

bit

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BitViper wrote:

> Here's the result.

Nice, although I think you don't really see lights on
the night side in real life when you also have the day
side within view (it's so much brighter).

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Christian Froeschlin wrote:
> BitViper wrote:
> 
>> Here's the result.
> 
> Nice, although I think you don't really see lights on the night side
> in real life when you also have the day side within view (it's so
> much brighter).

Well, since the camera is outside the atmosphere, it is dark all around 
you, no ambient light blocking out the darkness nearby, as would be the 
case looking into a dark cave or building from just outside in the 
light. So I do think the night side lights would be visible, however ...

I do think the the day/night line in the scene, as currently produced, 
is a bit sharp, and that if properly faded, the lights near the blend 
would/should indeed be at least much less visible.

The planet currently has no actual atmosphere, altho the cloud layer is 
actually a separate object 30 scale kilometers above the surface. So far 
my attempts to create a suitable atmosphere media have been somewhat 
less than impressive. They have however actually had the above mentioned 
effect of blending the day/night line.

I need to learn more about media. Along with my work on jupiters rings 
(see other thread in this group), this is my first time really playing 
with medias. Thanks to posts by someone else working on juipters rings 
in the other thread, I managed to get a very nice ring media working, 
altho it takes for freaking ever to render (1/2 hour this morning on a 
2.2ghz amd phenom quad with the 3.7.34 beta). Now to figure out an earth 
atmosphere.

Suggestions welcome, but I do enjoy figuring things out myself too.

bit

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BitViper <nom### [at] nowherebin> wrote:
> Sherry Shaw wrote:
>
> > Ambient goes in the "finish" block:
>
> Sweeeeeet! That did it. I forgot about the finish, have only used it
> twice in all of my playing with povray. Needless to say until now I
> havent gotten into the fancy things.
>
> Here's the result.
>
> http://www.bitviper.org/solarsystem/earth_lights.png
>
> bit

That is pretty nifty looking.  Too bad about the shadow line artifact.  Have you
tried using no_shadow?

-Reactor

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BitViper wrote:

> Well, since the camera is outside the atmosphere, it is dark all around 
> you, no ambient light blocking out the darkness nearby, as would be the 
> case looking into a dark cave or building from just outside in the 
> light. So I do think the night side lights would be visible

I think these light maps are generated by satellites in low
earth orbits so they essentially have a complete night without
day light in their field of view. Even so it may be a new moon
is also required to detect city lights.

Found a bit of info here:

   http://earthobservatory.nasa.gov/Features/Lights/lights_2.php

But feel free to use artistic license if you so desire ;)

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