Hi,

I've been using povray successfully over the years for various scientific
renders. And now I've hit an issue that I am not able to solve.

Basically my scene consists of various media with emission, absorption.
On top of that I add a large number of spheres defined as

#macro Star(Xx,Yy,Zz,Rr,Vr,Vg,Vb, Amb, Diff)
sphere { <Xx, Yy, Zz>, Rr
        texture {
                pigment {color rgb <Vr,Vg,Vb>}
                finish {
                       ambient Amb
                       diffuse Diff
                       }
                }
}

And I basically notice that when the number of those spheres in my scene  from
the file is >~ 149000, suddenly half of my image is rendered blank. (if the
number is below 149000, everything is rendered fine)

Clearly I'm hitting some kind of a limit. I tried to find an option to increase
to still render this, but was unsuccessful.

I am using povray 3.7.0.10.unofficial (from ubuntu).

are there any suggestions to deal with this ?

Thank you in advance,
         Sergey

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"segasai" <nomail@nomail> wrote:

> I am using povray 3.7.0.10.unofficial (from ubuntu).
>
> are there any suggestions to deal with this ?

1. Upgrade to 3.8
2. Try using boxes, blobs, or another simple primitive and see if the same sort
of thing happens.
3. If you put all of the spheres into a union and apply a single
pigment/texture, does the same thing happen?
4. What do the post-render statistic say about ray-object intersection tests?
5. What resolution is your render?  Where is your camera?  Is it static, or
dependent on the extent of where your spheres are?  Are there any sphere
quantity dependent things in your scene?
6. Post your scene code and people can investigate, look over the code, perform
tests, and put many heads together.

That's the best I can suggest off the top of my head without knowing more.

- BE

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On 21.01.2025 3:15, segasai wrote:

> And I basically notice that when the number of those spheres in my scene  from
> the file is >~ 149000, suddenly half of my image is rendered blank. (if the
> number is below 149000, everything is rendered fine)

Does something change if you increase  max_trace_level, for example?

-- 
Ilyich the Toad
https://dnyarri.github.io/

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Le 2025-01-20 à 19:15, segasai a écrit :
> Hi,
> 
> I've been using povray successfully over the years for various scientific
> renders. And now I've hit an issue that I am not able to solve.
> 
> Basically my scene consists of various media with emission, absorption.
> On top of that I add a large number of spheres defined as
> 
> #macro Star(Xx,Yy,Zz,Rr,Vr,Vg,Vb, Amb, Diff)
> sphere { <Xx, Yy, Zz>, Rr
>          texture {
>                  pigment {color rgb <Vr,Vg,Vb>}
>                  finish {
>                         ambient Amb
>                         diffuse Diff
>                         }
>                  }
> }
> 
> And I basically notice that when the number of those spheres in my scene  from
> the file is >~ 149000, suddenly half of my image is rendered blank. (if the
> number is below 149000, everything is rendered fine)
> 
> Clearly I'm hitting some kind of a limit. I tried to find an option to increase
> to still render this, but was unsuccessful.
> 
> I am using povray 3.7.0.10.unofficial (from ubuntu).
> 
> are there any suggestions to deal with this ?
> 
> Thank you in advance,
>           Sergey

I'm assuming that as they are all stars, they are all self illuminating.
Try this :

#default finish{diffuse 0 ambient 0 emission 1}
and don't use finish when creating the spheres. OR, use the finish only 
to set the emission value.
Need to use version 3.8. While it's still in beta, it's still very stable.

Can you sort your spheres by colour ?
Is so, bundle the sphere sharing the same colours in an union and apply 
that colour to the union.

You can pass vectors to a macro. So, you can change it to :

#macro Star(Position,Rr,Colour, Amb, Diff)
sphere { Position, Rr
         texture {
                 pigment {color rgb Colour}
                 finish {
                        ambient Amb
                        diffuse Diff
                        }
                 }}

Does moving the camera around a circle change what you see ?
If yes, you may have a range of values that is to large, leading to a 
catastrophic loss of precision. When the coordinate of an object get to 
large, that object tend to disappear.
You may want to switch to a larger unit for the positions.
Try working in parsec.

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