Hi,

I've spent ages trying to figure out what's causing this. I'm trying to create a
paper lantern, so I've taken a sphere, used difference with two boxes to get a
horizontal slice of it, and then repeated this with slightly different sized
spheres each time, so as to create a sort of segmented sphere. Now, I've used
double_illuminate and hollow so as to place two spotlights inside, one for just
generally illuminating the inside, and another to create a soft patch of light
to simulate the lightbulb inside it. Now, this hasn't exactly worked. One of
the segments is lit, but all the others are dark. So, can anyone identify the
mistake I've made? Your help would be much appreciated. I'd post an image, but
I've just realised that you can't post attachments here. :(

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On Thu, 27 Dec 2007 18:37:21 EST, "ADK" <nomail@nomail> wrote:

>I've just realised that you can't post attachments here. :(

You can post attachments at povray.binaries.images. 
One thing to check; is your max_trace_level high enough? 

Regards
	Stephen

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ADK <nomail@nomail> wrote:
> Now, I've used
> double_illuminate and hollow so as to place two spotlights inside

  'hollow' has no effect on lighting. (Why would it?)

> One of
> the segments is lit, but all the others are dark.

  The surface hit directly by the light is illuminated, and it's shadowing
the other surfaces.

  Try making the surfaces partially transparent for the light to pass
through.

-- 
                                                          - Warp

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Thanks, I thought something was wrong because there was an immediate transition
from lit to dark from one segment to another, but it turns out it was just one
segment shadowing the others. Also, I took hollow as being hollow rather than
reading what it mean, I get it now.

Warp <war### [at] tagpovrayorg> wrote:
> ADK <nomail@nomail> wrote:
> > Now, I've used
> > double_illuminate and hollow so as to place two spotlights inside
>
>   'hollow' has no effect on lighting. (Why would it?)
>
> > One of
> > the segments is lit, but all the others are dark.
>
>   The surface hit directly by the light is illuminated, and it's shadowing
> the other surfaces.
>
>   Try making the surfaces partially transparent for the light to pass
> through.
>
> --
>                                                           - Warp

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ADK nous apporta ses lumieres en ce 2007/12/27 18:37:
> Hi,
> 
> I've spent ages trying to figure out what's causing this. I'm trying to create a
> paper lantern, so I've taken a sphere, used difference with two boxes to get a
> horizontal slice of it, and then repeated this with slightly different sized
> spheres each time, so as to create a sort of segmented sphere. Now, I've used
> double_illuminate and hollow so as to place two spotlights inside, one for just
> generally illuminating the inside, and another to create a soft patch of light
> to simulate the lightbulb inside it. Now, this hasn't exactly worked. One of
> the segments is lit, but all the others are dark. So, can anyone identify the
> mistake I've made? Your help would be much appreciated. I'd post an image, but
> I've just realised that you can't post attachments here. :(
> 
> 
A little more effecient: Use an intersection of the sphere and one box.
And if you only want a shell, you can use clipped_by. It cut the object and 
leave the clipped part open.

Why use two lights, usualy, in a case like that, one with a looks_like is OK and 
faster.
With your aproach, you'll need another light if you see that object in a 
reflection, and need to adjust the direction of the light if you move the camera.
Set your "paper" as slightly transparent. Apply some normal with a small scale. 
  Add an interior with an ior. You may want to average several normals to get a 
smoother blured contour.
Place a light_source inside with a looks_like statement. Give it a 
fade_distance, and fade_power 2, with a value similar to the radius of the 
looks_like object and increase the value of the light to compansate.

hollow only purpose it to allow an object to contain some media.

-- 
Alain
-------------------------------------------------
You know you've been raytracing too long when people around you are astounded by 
the computer-animated tails they put on babies in The X-Files. You complain that 
it looks fake because they didn't bother to put in the tails' shadows.
Jeff Lee

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