Hi.

I've got an object made of smooth triangles, and I'm using radiosity and a
sky_sphere for lighting. When I render, there's unnatural-looking, very dark
shadows on some triangles - especially those that are nearly edge-on to the
camera. It looks like I've got the "smooth triangle bug" as described in the
VFAQ, but when I add 'double_illuminate', the shadows remain. The only way
I've found to remove them is ditch smooth_triangles, and go with regular
flat ones.

So, does the double_illuminate fix not work with radiosity, or am I looking
at a different problem altogether? these shadows are too sharp-edged to be
radiosity artefacts.

Yours,
Luke.

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Luke <Luk### [at] hotmailcom> wrote:
> So, does the double_illuminate fix not work with radiosity

  Radiosity does not take double_illuminate into account.
  Probably not an intentional behaviour.

-- 
plane{-x+y,-1pigment{bozo color_map{[0rgb x][1rgb x+y]}turbulence 1}}
sphere{0,2pigment{rgbt 1}interior{media{emission 1density{spherical
density_map{[0rgb 0][.5rgb<1,.5>][1rgb 1]}turbulence.9}}}scale
<1,1,3>hollow}text{ttf"timrom""Warp".1,0translate<-1,-.1,2>}//  - Warp -

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if it's unintentional behaviour, I'd LOVE TO SEE THIS FIXED.

Regards,
Apache

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Is this a mesh of triangles made from other software, or did you construct
the object yourself?  I've had meshes that I ran through PolyTrans, and when
they were smoothed I got strange holes and such in the objects.  In other
words, it is probably something wth the way the surface normals are being
calculated, and using another piece of software to calculate them might fix
it.

--
Douglas C. Eichenberg
dou### [at] nlsnet
http://www.getinfo.net/douge

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Apache <apa### [at] yahoocom> wrote:
> if it's unintentional behaviour, I'd LOVE TO SEE THIS FIXED.

  There was a thread about the subject some time ago. I don't remember
what was the final decision about 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 -

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Doug,
It's pure SDL (A little rope macro) and so entirely possible that I've got
the normals wrong. However, I think Warp had the right answer, so I'll be
using direct lighting for now.

Thanks all.
-Luke.

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Warp wrote:
> Luke <Luk### [at] hotmailcom> wrote:
> 
>>So, does the double_illuminate fix not work with radiosity
> 
> 
>   Radiosity does not take double_illuminate into account.
>   Probably not an intentional behaviour.
> 
I think it does.
See for example this:
http://news.povray.org/povray.binaries.images/25135/

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Simon Adameit wrote:
> Warp wrote:
> 
>> Luke <Luk### [at] hotmailcom> wrote:
>>
>>> So, does the double_illuminate fix not work with radiosity
>>
>>
>>
>>   Radiosity does not take double_illuminate into account.
>>   Probably not an intentional behaviour.
>>
> I think it does.
> See for example this:
> http://news.povray.org/povray.binaries.images/25135/
> 
After doing some tests I noticed that I am wrong. Radiosity does take 
double_illuminate into account only when the surface is illuminated by 
direct lights.

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