I have a large complex model which takes a 40s to render at 320x240 with two 
external light sources, but takes over 18m to render if I add in the 8 
lights within the object.  The model is totally CSG with no reflection or 
refraction.  I have used Phong and standard procedural textures.

To speed up the render I thought I'd use light_groups to limit the effect of 
the lights to nearby parts of the model.  Although it does limit the effect 
of the lights, unfortunately this has made no effect to the render times...

Is there a gotcha with light_groups I am missing?

Can anyone suggest any other solutions?

Here is a snippet of my code showing how the light_group is being used...

union
{
    object{UpperHead translate<50, 0, 0>}
    object{LowerHead translate<50, 0, 0>}
    light_group
    {
        object{MidHead translate<50, 0, 0>}
        light_group{MidHeadLights translate<50, 0, 0>}
        global_lights on
    }
    object{Neck translate<0, 0, 3>}
    object{Engines translate<-65, 0, 3>}
    object{Pods translate<0, 0, 0>}
}

Each of the objects (UpperHead, etc.) is a #local of a large CSG. 
MidHeadLights is a #local of a union of the 8 light_sources.

BTW I am using POVRay 3.7.0.beta.19/msvc8-sse2.win32 running on WinXP SP2, 
on a PentiumD (2x2.8GHz), with 1Gb DDR Ram.

Rarius

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Further to my earlier post... POVRay 3.6.1c manages to render the file in 
11m41s with the lights included against 3.7.0.beta19 in 18m41s.

Rarius

"Rarius" <rar### [at] rariuscouk> wrote in message 
news:45c28f26$1@news.povray.org...
>I have a large complex model which takes a 40s to render at 320x240 with 
>two external light sources, but takes over 18m to render if I add in the 8 
>lights within the object.  The model is totally CSG with no reflection or 
>refraction.  I have used Phong and standard procedural textures.
>
> To speed up the render I thought I'd use light_groups to limit the effect 
> of the lights to nearby parts of the model.  Although it does limit the 
> effect of the lights, unfortunately this has made no effect to the render 
> times...
>
> Is there a gotcha with light_groups I am missing?
>
> Can anyone suggest any other solutions?
>
> Here is a snippet of my code showing how the light_group is being used...
>
> union
> {
>    object{UpperHead translate<50, 0, 0>}
>    object{LowerHead translate<50, 0, 0>}
>    light_group
>    {
>        object{MidHead translate<50, 0, 0>}
>        light_group{MidHeadLights translate<50, 0, 0>}
>        global_lights on
>    }
>    object{Neck translate<0, 0, 3>}
>    object{Engines translate<-65, 0, 3>}
>    object{Pods translate<0, 0, 0>}
> }
>
> Each of the objects (UpperHead, etc.) is a #local of a large CSG. 
> MidHeadLights is a #local of a union of the 8 light_sources.
>
> BTW I am using POVRay 3.7.0.beta.19/msvc8-sse2.win32 running on WinXP SP2, 
> on a PentiumD (2x2.8GHz), with 1Gb DDR Ram.
>
> Rarius
>

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