>
> Do you know if the source for that image is available? There is a smoothness in
> the media which may solve or augment some issues I am working on at the moment.
>
> Ian
>

I post the source in p.t.scene.files, you can study, edit, use it as you 
like. I hope it will be usefull for you.

Lionel.


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>
> The way this macro works is by encapsulating the emitting media in a local
> sphere with intervals 2 and samples 10, 100, which avoids some of the issues I
> have experienced with global atmospheric media, in terms of undesired
> interactions and render time. I will inspect the link you sent further, however.
>

Again me!
Ok, I have clean up the code and here is an example of the fake glow 
(sphere encapsuled in another sphere). Source is in p.t.scene-file under 
/fake glow/ subject.

Lionel.


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Preview of image 'fake_glow.png'

> Hello again! I just want to thank you for your Metal and Media texture
> contributions [see our e-mail from 11/11/13]. I promise you will see them in
> action soon, shortly after I am done with improving my blob placement engine
> used in my Snow, Moss and Corrosion macros. :)
>
> The way this macro works is by encapsulating the emitting media in a local
> sphere with intervals 2 and samples 10, 100, which avoids some of the issues I
> have experienced with global atmospheric media, in terms of undesired
> interactions and render time. I will inspect the link you sent further, however.
>
> Do you know if the source for that image is available? There is a smoothness in
> the media which may solve or augment some issues I am working on at the moment.
>
> Ian
>
>
>

As the default sampling method for media is method 3, using intervals 
with a value larger than 1 have very bad effec on the rendering time. 
Also, as the documentation state, "Too many intervals can lead to 
artifacts, and POV will create more intervals if it needs them."
The default is 1 and should be left at that.

Also, samples 10, 100 is the same as samples 10. ONLY the first value is 
used and the second is silently ignored.

Similarly, ratio, been needed to determine the relative weight of the 
intervals, no longer have any object and is not used.
The same apply to confidance and variance as they are used to decide if 
you need more samples for an interval or not.

The default values are:
method 3
samples 10
intervals 1

variance is NOT used
confidance is NOT used
ratio is NOT used



Alain

Post a reply to this message

Alain <kua### [at] videotronca> wrote:

>
> The default values are:
> method 3
> samples 10
> intervals 1
>
> variance is NOT used
> confidance is NOT used
> ratio is NOT used
>

I've been wondering about the usefulness of variance/confidence/ratio for a long
time (re: method 3). I came to the same conclusions, after a lot of testing and
head-scratching. It's nice to see the info clearly stated. :-)

Post a reply to this message

Alain <kua### [at] videotronca> wrote:
> As the default sampling method for media is method 3, using intervals
> with a value larger than 1 have very bad effec on the rendering time.
> Also, as the documentation state, "Too many intervals can lead to
> artifacts, and POV will create more intervals if it needs them."
> The default is 1 and should be left at that.
>
> Also, samples 10, 100 is the same as samples 10. ONLY the first value is
> used and the second is silently ignored.
>
> Similarly, ratio, been needed to determine the relative weight of the
> intervals, no longer have any object and is not used.
> The same apply to confidance and variance as they are used to decide if
> you need more samples for an interval or not.
>
> The default values are:
> method 3
> samples 10
> intervals 1
>
> variance is NOT used
> confidance is NOT used
> ratio is NOT used
>
>
>
> Alain

That is a lot of info that I did not know, there; thank you! :)

I am using method 2 exclusively, but now that I know the second number is
pointless, I'll remove it for cleanliness. I do not use variance, confidence or
ratio either. :)

Ian

Post a reply to this message

FractRacer <lg.### [at] gmailcom> wrote:
> Again me!
> Ok, I have clean up the code and here is an example of the fake glow
> (sphere encapsuled in another sphere). Source is in p.t.scene-file under
> /fake glow/ subject.
>
> Lionel.

Thanks! :)

The effects you have there look pretty sweet too. :)

Ian

Post a reply to this message

> Alain <kua### [at] videotronca> wrote:
>> As the default sampling method for media is method 3, using intervals
>> with a value larger than 1 have very bad effec on the rendering time.
>> Also, as the documentation state, "Too many intervals can lead to
>> artifacts, and POV will create more intervals if it needs them."
>> The default is 1 and should be left at that.
>>
>> Also, samples 10, 100 is the same as samples 10. ONLY the first value is
>> used and the second is silently ignored.
>>
>> Similarly, ratio, been needed to determine the relative weight of the
>> intervals, no longer have any object and is not used.
>> The same apply to confidance and variance as they are used to decide if
>> you need more samples for an interval or not.
>>
>> The default values are:
>> method 3
>> samples 10
>> intervals 1
>>
>> variance is NOT used
>> confidance is NOT used
>> ratio is NOT used
>>
>>
>>
>> Alain
>
> That is a lot of info that I did not know, there; thank you! :)
>
> I am using method 2 exclusively, but now that I know the second number is
> pointless, I'll remove it for cleanliness. I do not use variance, confidence or
> ratio either. :)
>
> Ian
>

When using method 2, you NEED to provide intervals, variance, confidance 
and ratio, or rely on the default values. Also, you should use samples 
min_samples, max_samples.

Post a reply to this message

Alain <kua### [at] videotronca> wrote:
> When using method 2, you NEED to provide intervals, variance, confidance
> and ratio, or rely on the default values. Also, you should use samples
> min_samples, max_samples.

That is pretty much what I have going on, save for variance, confidence and
ratio. I do not really know the details of cause and effect well enough to mess
with them, and I am extremely close to my goal of replicating MP Glows [types 1
and 2] now. I have a total of 11 Glow types at this point, and they are all
distinct enough where it isn't easy to confuse them.

One thing I tried was converting the C code from the Glow patch to SDL, as much
as was possible. I spent an hour or so doing that, but it was cumbersome because
it required parameters that I know of no way to access in SDL, such as ray
origin and various extents. I did this back in my first stab a few years ago;
perhaps I'll look at this again with an eye towards simply extracting the
falloff expressions.

One outlier is attached...I have no idea what is up with this odd cube
artifact... It almost looks like bounding boxes, but I wouldn't put money on
that being what it is. I replicated this accident once through overlapping media
containers and looks_like [quickly fixed through consolidation], but such is not
the case in this instance. This is the shabbiest example of what I have
accomplished toward my goal, by the way.

Once I am happy with the 11 types, I will consolidate the SDL to remove
duplicate code across types, remove anything that ends up being too close to
anything else, and to minimize light sources.

The FixedSimpleVector exceptions I was getting are gone now through prior
consolidation efforts, but I have not yet established a comparison of max glows
between MP and the media variant. Obviously the media implementation is slower
to varying degrees according to type.

Thanks for the tips man! :)

Ian

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Attachments:
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Preview of image 'mediaglow 2014_0_2_.png'