I need to simulate a glowing gem. Now I know we cant get things to glow on
their own and there is something called radiosity that can simulate this. I
have never used radiosity before though. The object in question is just a
simple blue sphere. what coding can I put to make it simulate glowing?
Thanks for any help.

Post a reply to this message

> I need to simulate a glowing gem. Now I know we cant get things to glow on
> their own and there is something called radiosity that can simulate this.
I
> have never used radiosity before though. The object in question is just a
> simple blue sphere. what coding can I put to make it simulate glowing?
> Thanks for any help.

Although radiosity can be used with a high ambient value to cause an object
to emit light, it's probably better to just use an actual light_source with
the looks_like keyword. To make the sphere itself appear bright, you can use
a high ambient value or emission media; this was recently discussed briefly
in the thread "Grr... I want it to GLOW!!!" in povray.newusers.

 - Slime
 [ http://www.slimeland.com/ ]

Post a reply to this message

Slime wrote:

>> have never used radiosity before though. The object in question is just a
>> simple blue sphere. what coding can I put to make it simulate glowing?
>> Thanks for any help.
 
> Although radiosity can be used with a high ambient value to cause an
> object to emit light, it's probably better to just use an actual
> light_source with the looks_like keyword. To make the sphere itself appear
> bright, you can use a high ambient value or emission media; this was
> recently discussed briefly in the thread "Grr... I want it to GLOW!!!" in
> povray.newusers.

To summ up:

ambient:
+ very soft shadows, exacly same shape as object
- light comming from radiosity can not cause speculars and other light
effects

light_source:
+ fast
+ can produce highlights, photons, media, and so on
- is only a point (shadow can look like cased from sphere, rectangle or box)

union of many small light_source:
+ is very accuarate, can be almost as detailed as ambient-based light
- is very slow
+ but can be speeded up using light_group

So I would suggest to combine this light models, in example 
* an ambient object
* light_source in center with smooth area_light
* few smaller light_sources with less detailed area_light, number and
quality based on scene quality settings 




-- 
Rafal Maj Raf256

Post a reply to this message

Barehunter <nomail@nomail> wrote:
> I need to simulate a glowing gem. Now I know we cant get things to glow on
> their own and there is something called radiosity that can simulate this. I
> have never used radiosity before though. The object in question is just a
> simple blue sphere. what coding can I put to make it simulate glowing?

  That depends on whether you want it to just emit light or whether
you want a visible halo around it.

-- 
#macro M(A,N,D,L)plane{-z,-9pigment{mandel L*9translate N color_map{[0rgb x]
[1rgb 9]}scale<D,D*3D>*1e3}rotate y*A*8}#end M(-3<1.206434.28623>70,7)M(
-1<.7438.1795>1,20)M(1<.77595.13699>30,20)M(3<.75923.07145>80,99)// - Warp -

Post a reply to this message

Slime <fak### [at] emailaddress> wrote:
> Although radiosity can be used with a high ambient value to cause an object
> to emit light, it's probably better to just use an actual light_source with
> the looks_like keyword.

  The looks_like object is shadowless, and in the case of a softly
glowing gem, it probably should not be.
  Just create the gem and put a light source inside it and that's it.

-- 
#macro N(D)#if(D>99)cylinder{M()#local D=div(D,104);M().5,2pigment{rgb M()}}
N(D)#end#end#macro M()<mod(D,13)-6mod(div(D,13)8)-3,10>#end blob{
N(11117333955)N(4254934330)N(3900569407)N(7382340)N(3358)N(970)}//  - Warp -

Post a reply to this message