Having trouble seeing any scattering effects from the media I'm putting in. I've
added two lines to my code:

"light_source{<30,0,0> 0.3 media_interaction off}"
to light the room

and

box{<-20,-32,-20>,<10,8,20> pigment {rgbt 1} hollow interior {media{scattering{1
,0.07 extinction 0.01} samples 1000,10000}}}

to scatter the light.

However, I'm not seeing anything. Are my values for the scattering or sampling
not in the right ballpark to see the effect, or is something else going on here?

Thanks!

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I figured out my issues, which were numerous. Here is my current result:

http://yfrog.com/fvcode5int5samplesp

Took 22 minutes to render on my computer. I'm steping up the interval and
sampling rate to make a better image though. This program is mind-blowingly fun
:)

Thanks for all the help. No more questions in this thread :)

Post a reply to this message

> Moving the disco ball to the top makes it look a little better just because the
> walls aren't all the same anymore.
>
> http://yfrog.com/f7codekp
>
>
The right and left spots are geting several colours. It looks like you 
have several pieces at those locations.

For the shadow behing the ball, you can try placing the light farther 
back or make it shadowless.

To render the beams visible, you need to add some scattering media into 
your room. Read the interior and media sections of the documentation.



Alain

Post a reply to this message

> I figured out my issues, which were numerous. Here is my current result:
>
> http://yfrog.com/fvcode5int5samplesp
>
> Took 22 minutes to render on my computer. I'm steping up the interval and
> sampling rate to make a better image though. This program is mind-blowingly fun
> :)
>
> Thanks for all the help. No more questions in this thread :)
>
>

Don't increase the intervals value as it will kill your render times. 
Only increase samples.

samples 100 will render faster than intervals 10 samples 5 for twice the 
total samples.

While you can use samples 10, 100, only the "10" will be used ans the 
"100" will be totaly ignored.

The defaults value from the documentation are for smpling method 1. The 
default sampling method is method 3. It's defaults are:
intervals 1 // NEVER change that!
samples 10 // MUST be 3 or larger.


Alain

Post a reply to this message

> On 03/10/2010 9:49 PM, Brad wrote:
>> Is there a way for me to visualize the light rays that are hitting the
>> wall, as
>> if there were dust in the air? Would I just fill the observable area
>> with a
>> white box with almost perfect transparency? Or is there a more
>> professional way
>> to do this (surely....)?
>
> You will need to use photons and fill the scene with scattering media.
> Read 3.6.2.1 Media Types
> And for an example look at optics.pov in \POV-Ray\v3.7\scenes\advanced
>
> To make this work the container for the media needs the "hollow" flag set.
> 3.4.9.5 Hollow.
>
> Fun, fun, fun ;-)
>

You DON'T need photons in this case. The light only goes straight 
through the transparent parts, thus no refraction, and there are no 
reflection.


Alain

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Thanks for these additional comments Alain. However, before I read them I
already ran a case at 20 samples and 20 iterations, with the output below (and
also rotating the cube a bit so the light isn't shining in the camera's eyes).

http://yfrog.com/2mcode20int20samplesp

It took a little over 4 hours to render on my desktop (ran it overnight). I can
really see how those doing much, much more complicated scenes run into
ridiculous rendering times.

Alain <aze### [at] qwertyorg> wrote:

> > I figured out my issues, which were numerous. Here is my current result:
> >
> > http://yfrog.com/fvcode5int5samplesp
> >
> > Took 22 minutes to render on my computer. I'm steping up the interval and
> > sampling rate to make a better image though. This program is mind-blowingly fun
> > :)
> >
> > Thanks for all the help. No more questions in this thread :)
> >
> >
>
> Don't increase the intervals value as it will kill your render times.
> Only increase samples.
>
> samples 100 will render faster than intervals 10 samples 5 for twice the
> total samples.
>
> While you can use samples 10, 100, only the "10" will be used ans the
> "100" will be totaly ignored.
>
> The defaults value from the documentation are for smpling method 1. The
> default sampling method is method 3. It's defaults are:
> intervals 1 // NEVER change that!
> samples 10 // MUST be 3 or larger.
>
>
> Alain

Post a reply to this message

> Thanks for these additional comments Alain. However, before I read them I
> already ran a case at 20 samples and 20 iterations, with the output below (and
> also rotating the cube a bit so the light isn't shining in the camera's eyes).
>
> http://yfrog.com/2mcode20int20samplesp
>
> It took a little over 4 hours to render on my desktop (ran it overnight). I can
> really see how those doing much, much more complicated scenes run into
> ridiculous rendering times.
>
> Alain<aze### [at] qwertyorg>  wrote:

>>> I figured out my issues, which were numerous. Here is my current result:
>>>
>>> http://yfrog.com/fvcode5int5samplesp
>>>
>>> Took 22 minutes to render on my computer. I'm steping up the interval and
>>> sampling rate to make a better image though. This program is mind-blowingly fun
>>> :)
>>>
>>> Thanks for all the help. No more questions in this thread :)
>>>
>>>
>>
>> Don't increase the intervals value as it will kill your render times.
>> Only increase samples.
>>
>> samples 100 will render faster than intervals 10 samples 5 for twice the
>> total samples.
>>
>> While you can use samples 10, 100, only the "10" will be used ans the
>> "100" will be totaly ignored.
>>
>> The defaults value from the documentation are for smpling method 1. The
>> default sampling method is method 3. It's defaults are:
>> intervals 1 // NEVER change that!
>> samples 10 // MUST be 3 or larger.
>>
>>
>> Alain
>
>
>
>
I notted an anomaly in your scene:
The spots are set into 6 sets of 9, for a total of 56. The problem is 
that you have 84 cylinders, and looking further, you have LOTS of 
duplicates like: <0,0,10> <-0,0,10> <0,-0,10> and <-0,-0,10> with many 
apearing in 2 or even 3 colours sets. (manualy changing very small 
values to zeros helped a lot to spot those)
Those duplicates increase your render time and cause coincident surfaces 
artefacts each time that you have more than 1 colour at the same place.



Alain

Post a reply to this message

>> Thanks for these additional comments Alain. However, before I read them I
>> already ran a case at 20 samples and 20 iterations, with the output
>> below (and
>> also rotating the cube a bit so the light isn't shining in the
>> camera's eyes).
>>
>> http://yfrog.com/2mcode20int20samplesp
>>
>> It took a little over 4 hours to render on my desktop (ran it
>> overnight). I can
>> really see how those doing much, much more complicated scenes run into
>> ridiculous rendering times.
>>
>> Alain<aze### [at] qwertyorg> wrote:

>>>> I figured out my issues, which were numerous. Here is my current
>>>> result:
>>>>
>>>> http://yfrog.com/fvcode5int5samplesp
>>>>
>>>> Took 22 minutes to render on my computer. I'm steping up the
>>>> interval and
>>>> sampling rate to make a better image though. This program is
>>>> mind-blowingly fun
>>>> :)
>>>>
>>>> Thanks for all the help. No more questions in this thread :)
>>>>
>>>>
>>>
>>> Don't increase the intervals value as it will kill your render times.
>>> Only increase samples.
>>>
>>> samples 100 will render faster than intervals 10 samples 5 for twice the
>>> total samples.
>>>
>>> While you can use samples 10, 100, only the "10" will be used ans the
>>> "100" will be totaly ignored.
>>>
>>> The defaults value from the documentation are for smpling method 1. The
>>> default sampling method is method 3. It's defaults are:
>>> intervals 1 // NEVER change that!
>>> samples 10 // MUST be 3 or larger.
>>>
>>>
>>> Alain
>>
>>
>>
>>
> I notted an anomaly in your scene:
> The spots are set into 6 sets of 9, for a total of 56. The problem is
> that you have 84 cylinders, and looking further, you have LOTS of
> duplicates like: <0,0,10> <-0,0,10> <0,-0,10> and <-0,-0,10> with many
> apearing in 2 or even 3 colours sets. (manualy changing very small
> values to zeros helped a lot to spot those)
> Those duplicates increase your render time and cause coincident surfaces
> artefacts each time that you have more than 1 colour at the same place.
>
>
>
> Alain
After removing 18 duplicates (6 for each colours, only for the 
orthogonals ones and not checking between colours sets), I got an 
impressive boost in my render time. Down to 66 elements down from the 
original 84. Sould be further reduced to 54.
Still have 3 for <0,0,10> and <0,0,-10> that have all 3 colours. 
Resolving those removes 4 more elements-> down to 62.

It should be noted that intersection and difference are inherently poor 
at bounding: Any ray that encounter those need to be tested against all 
components. This also apply to the shadow rays. So the less components 
you have, the faster the shadow rays can be evaluated.

I'm thinking of another aproach:
Have only a plain sphere and place a collection of tight spot_light in 
it's center. Add double_illuminate to make the spots visible on the 
surface. Add no_shadow so that the beams can continue outside of the sphere.
You use the points that you have presently as the point_at for the spots.
Now, any duplicate will be obvious due to the increased lighting.



Alain

Post a reply to this message

> I'm thinking of another aproach:
> Have only a plain sphere and place a collection of tight spot_light in
> it's center. Add double_illuminate to make the spots visible on the
> surface. Add no_shadow so that the beams can continue outside of the
> sphere.
> You use the points that you have presently as the point_at for the spots.
> Now, any duplicate will be obvious due to the increased lighting.
>
>
>
> Alain

Using that, I got some dramatic speed improvement, about 20 times faster.
The only thing been that if you want to see the bright spots the sphere 
can't be black. It can be dark and using fading lights that are very 
bright at short distance the spots will show as bright coloured areas.


Alain

Post a reply to this message

Alain <aze### [at] qwertyorg> wrote:

>
> > I'm thinking of another aproach:
> > Have only a plain sphere and place a collection of tight spot_light in
> > it's center. Add double_illuminate to make the spots visible on the
> > surface. Add no_shadow so that the beams can continue outside of the
> > sphere.
> > You use the points that you have presently as the point_at for the spots.
> > Now, any duplicate will be obvious due to the increased lighting.
> >
> >
> >
> > Alain
>
> Using that, I got some dramatic speed improvement, about 20 times faster.
> The only thing been that if you want to see the bright spots the sphere
> can't be black. It can be dark and using fading lights that are very
> bright at short distance the spots will show as bright coloured areas.
>
>
> Alain

Thanks for all those additional suggestions and the catching of duplicates
Alain, I really appreciate it! I'm out of town at the moment but I look forward
to playing around with some of your suggestions once I get back.

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