sorrry, I should have mentioned the time needed.
It takes about 10 minutes with a 2.7 GHz P4 system to complete the 
coordinate finding for the 75000 trees.
You need an aspect ratio of 2:1 like in +w800 +h400 despite ending with a 
black image.
After you generated the tree coordinates once parsing the Tree_Logo.pov file 
needs only 20 seconds.

Norbert Kern

"EagleSun" <nomail@nomail> schrieb im Newsbeitrag 
news:4323a659@news.povray.org...
>
> "Norbert Kern" <nor### [at] t-onlinede> wrote in message 
> news:43236855@news.povray.org...
>> This demo scene shows three effects useful for planting many things like
>> grass, trees, rocks or stones.
>>
>> 1. If you want to show a dense forest from near to a far distance, you 
>> may
>> need millions of tree copies. Even povray has problems with millions of
>> mesh2 copies.
>> But if you show only the visible ones, you need only 75000 trees like in
>> this demo file.
>> The trick is to define random vectors from the camera position, which 
>> point
>> only to visible parts and to use them in the trace command.
>>
>> 2. The problem with this method is that parts far away seem less dense
>> populated as nearer parts.
>> The solution is to find the maximum distance to be populated. Then you 
>> can
>> use the inverse quadratic relationship to plant with equal density 
>> despite
>> different distances.
>>
>> 3. I always wanted to draw directly on a test image and to use it for
>> different planting effects. This would give maximum control over the 
>> result.
>> The second image shows the POV logo's image used in the demo scene.
>>
>> I'll post an (unoptimized) demo file at binaries.scene-files.
>
> Really NICE photo!  (tho not sure it's allowed here) hehe.
>
> Still trying to figure out what you're saying here.. cause I'm a novice 
> with POV-Ray.  Sounds like you're trying to define only those trees that 
> are in view, and not ALL the trees.... when I ran the 
> veg_many_things_WRITE script... I gave up waiting for it to finish, and I 
> think it did only 300 trees.  Not sure this shortcut of yours is anything 
> short at all.
>
>

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