Thomas de Groot wrote:
> "Tek" <tek### [at] evilsuperbraincom> schreef in bericht 
> news:463dcd87@news.povray.org...
>   
>> Swirly effect! I added a radial normal to my distortion effect, which is 
>> ramped up towards the middle of the effect to things get swirled more the 
>> closer they get.
>>
>>     
>
> Nice indeed! Much better.
> I agree with Gail about the ring. I imagine that the black hole would be 
> totally black.... Now, where did I read that black holes would have a 
> slightly bluish glow...??? I can't remember.
>
> Thomas
>
>
>   
Makes you wonder what happens to the light that comes from a point 
between us and the event horizon.

Post a reply to this message

Art Flint nous apporta ses lumieres en ce 7 / 05 / 2007 07:19:

> Makes you wonder what happens to the light that comes from a point 
> between us and the event horizon.

Red shift!

Post a reply to this message

Okay, I can't shut up any longer. :-)

First off, the image is awesome. Your ship is great, your nebulae are 
beautiful, and the black hole is trippy-cool.

Now, a personal pet peeve: In space, there is no "ambient" light. 
There's no atmospheric scattering of light, so shadows are *black*. Take 
a look at a crescent moon, and you'll see what I mean.

Almost everybody gets this wrong, including Hollywood. :-) At the same 
time, I think there's some new artistic ground to cover here--you can 
create some *really* dramatic images by fixing the shadows.

The big challenge is making the object still be *visible* when half of 
it is black, and it is against a black background. I'm still kicking 
some ideas around in my head for dealing with this.

You could bend physics a little with the lighting :-) such that both 
edges of the craft are highlighted, outlining it and making the shape 
visible.

Alternatively, you could take the route of not having space actually be 
black. Make the stars a lot more dense, and beef up the nebulae until 
the dark parts of the ship are silhouetted against the background. Take 
a look at this guy's backgrounds: http://www.crimsondark.com (note that 
he gets the shadows wrong, too...)

Finally, you could not go *all* the way, and just darken the shadows as 
far as you can without making them actually disappear.

Or, you being The Incredible Tek, ;-) you could just come up with 
something way better than anything I can imagine.

Anyway, the image is great as it is. Right now it's up there with 
Hollywood. I just feel that you can do one better than Hollywood. :-D

-- 
William Tracy
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|a|f|i|s|h|i|o|n|a|d|o|@|g|m|a|i|l|.|c|o|m|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|w|t|r|a|c|y|@|c|a|l|p|o|l|y|.|e|d|u|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

You know you've been raytracing too long when you were ever dragged out 
of a theater for yelling "Cheap rasterized graphics!!!" in the middle of 
Toy Story.
Stephan Ahonen

Post a reply to this message

"William Tracy" <wtr### [at] calpolyedu> wrote in message
news:463f82bf$1@news.povray.org...

> Now, a personal pet peeve: In space, there is no "ambient" light.

There's still light reflected off other objects, planets, other ships, etc

> There's no atmospheric scattering of light, so shadows are *black*. Take
> a look at a crescent moon, and you'll see what I mean.

Actually, even with a crescent moon, the parts unlit by the sun are
relativly bright, from light reflected off the nearly full earth.
http://antwrp.gsfc.nasa.gov/apod/ap070428.html

Post a reply to this message

"Tek" <tek### [at] evilsuperbraincom> wrote:

> Uh... anyway... The cool black hole effect is achieved with a refractive
> object shaped so that it has no refraction at the edges when viewed from the
> camera's point of view, effectively making it a 2D distortion. I then use
> several such objects at different distances to create the event horizon, the
> "sucking" effect, and the smaller distortion on the ship.

Cool.  It looks a little sharper at the edges than I would have expected.  I
read that book "Black Holes and Time Warps" or something by Kip Thorne, but
I don't remember exactly how things LOOK as they fall in.  It would be an
interesting patch though to actually simulate it.  No idea how it's done,
but it looks like raytracing has been applied to both special and general
relativity.  A cool gif of a black hole on the page.

http://www.tat.physik.uni-tuebingen.de/~tmueller/visual.html

 - Ricky

Post a reply to this message

"Gail Shaw" <initialsurname@sentech sa dot com> wrote in message 
news:463f956c@news.povray.org...
>
> "William Tracy" <wtr### [at] calpolyedu> wrote in message
> news:463f82bf$1@news.povray.org...
>
>> Now, a personal pet peeve: In space, there is no "ambient" light.
>
> There's still light reflected off other objects, planets, other ships, etc

Exactly! I have 0 ambient, it's all just light from the nebulae and bounced 
off the ship (2-bounce radiosity).
Also you'll note the sunlight is incredibly bright because the brightness of 
the image is adjusted to allow you to see nebulae (which would normally be 
nearly black in a scene with such a bright sun, but I'm using a high 
exposure so the directly lit surfaces saturate to white and we can see 
details in the shadow). I think I've used fairly realistic lighting for a 
star that's a bit further away than our sun.

>> There's no atmospheric scattering of light, so shadows are *black*. Take
>> a look at a crescent moon, and you'll see what I mean.
>
> Actually, even with a crescent moon, the parts unlit by the sun are
> relativly bright, from light reflected off the nearly full earth.
> http://antwrp.gsfc.nasa.gov/apod/ap070428.html

Great example :)

-- 
Tek
http://evilsuperbrain.com

Post a reply to this message

(with reference to my reply to Gail's post)

Here's a version taken with a lower exposure. I've lowered the exposure 
enough to stop the lit side from saturating, so now you can see how much 
darker the dark side is. Though it's still not black since there are a lot 
of nebulae

-- 
Tek
http://evilsuperbrain.com


"William Tracy" <wtr### [at] calpolyedu> wrote in message 
news:463f82bf$1@news.povray.org...
> Okay, I can't shut up any longer. :-)
>
> First off, the image is awesome. Your ship is great, your nebulae are
> beautiful, and the black hole is trippy-cool.
>
> Now, a personal pet peeve: In space, there is no "ambient" light.
> There's no atmospheric scattering of light, so shadows are *black*. Take
> a look at a crescent moon, and you'll see what I mean.
>
> Almost everybody gets this wrong, including Hollywood. :-) At the same
> time, I think there's some new artistic ground to cover here--you can
> create some *really* dramatic images by fixing the shadows.
>
> The big challenge is making the object still be *visible* when half of
> it is black, and it is against a black background. I'm still kicking
> some ideas around in my head for dealing with this.
>
> You could bend physics a little with the lighting :-) such that both
> edges of the craft are highlighted, outlining it and making the shape
> visible.
>
> Alternatively, you could take the route of not having space actually be
> black. Make the stars a lot more dense, and beef up the nebulae until
> the dark parts of the ship are silhouetted against the background. Take
> a look at this guy's backgrounds: http://www.crimsondark.com (note that
> he gets the shadows wrong, too...)
>
> Finally, you could not go *all* the way, and just darken the shadows as
> far as you can without making them actually disappear.
>
> Or, you being The Incredible Tek, ;-) you could just come up with
> something way better than anything I can imagine.
>
> Anyway, the image is great as it is. Right now it's up there with
> Hollywood. I just feel that you can do one better than Hollywood. :-D
>
> -- 
> William Tracy
> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
> |a|f|i|s|h|i|o|n|a|d|o|@|g|m|a|i|l|.|c|o|m|
> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
> |w|t|r|a|c|y|@|c|a|l|p|o|l|y|.|e|d|u|
> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
>
> You know you've been raytracing too long when you were ever dragged out
> of a theater for yelling "Cheap rasterized graphics!!!" in the middle of
> Toy Story.
> Stephan Ahonen

Post a reply to this message

Attachments:
Download 'space simple.jpg' (64 KB)

Preview of image 'space simple.jpg'

Alain wrote:
> Art Flint nous apporta ses lumieres en ce 7 / 05 / 2007 07:19:
>
>> Makes you wonder what happens to the light that comes from a point 
>> between us and the event horizon.
>
> Red shift!
So anything that comes from above the visible ligth range might be 
shifted down to a bluish color?

Post a reply to this message

Art Flint nous apporta ses lumieres en ce 7 / 05 / 2007 21:29:
> Alain wrote:
>> Art Flint nous apporta ses lumieres en ce 7 / 05 / 2007 07:19:
>>
>>> Makes you wonder what happens to the light that comes from a point 
>>> between us and the event horizon.
>>
>> Red shift!
> So anything that comes from above the visible ligth range might be 
> shifted down to a bluish color?
Yes, and possibly more. If blue shift to red, then about all of the UV will 
become visible from red to blue, X-rays will degrade to UV A and B and gamma 
rays will become UV C and X-rays. If you go closer, then even gamma rays could 
degrade into low frequency radio waves...

-- 
Alain
-------------------------------------------------
Don't kiss an elephant on the lips today.

Post a reply to this message

triple_r nous apporta ses lumieres en ce 7 / 05 / 2007 17:25:
> "Tek" <tek### [at] evilsuperbraincom> wrote:
> 
>> Uh... anyway... The cool black hole effect is achieved with a refractive
>> object shaped so that it has no refraction at the edges when viewed from the
>> camera's point of view, effectively making it a 2D distortion. I then use
>> several such objects at different distances to create the event horizon, the
>> "sucking" effect, and the smaller distortion on the ship.
> 
> Cool.  It looks a little sharper at the edges than I would have expected.  I
> read that book "Black Holes and Time Warps" or something by Kip Thorne, but
> I don't remember exactly how things LOOK as they fall in.  It would be an
> interesting patch though to actually simulate it.  No idea how it's done,
> but it looks like raytracing has been applied to both special and general
> relativity.  A cool gif of a black hole on the page.
> 
> http://www.tat.physik.uni-tuebingen.de/~tmueller/visual.html
> 
>  - Ricky
> 
The visible star may not be faling in, it may be a great distance BEHIND the 
black hole, then, it's light gets bent, the closer the light pass by the black 
hole, the more it get's bent, leading to the observed distortion.

-- 
Alain
-------------------------------------------------
Tricks and treachery are the practice of fools, that don't have brains enough to 
be honest.
Benjamin Franklin

Post a reply to this message