On 30/10/2017 09:51, clipka wrote:
> Am 29.10.2017 um 11:12 schrieb Stephen:
>> On 29/10/2017 01:12, clipka wrote:
>>> Am 28.10.2017 um 22:15 schrieb Stephen:
>>>

>>>>>
>>>>
>>>> :D
>>>>
>>>> Clipka used to post mails with weird time stamps too. ;)
>>>
>>> Did I?
>>> I don't recall anything like that.
>>> I do remember /seeing/ posts with weird time stamps.
>>>
>>
>> If I remember correctly it was the time stamp. For a while your posts
>> seemed to be posted in the wee sma' hours, UK time.
> 
> Ah, now I get you.
> 
> Well, yes, that used to happen, for some inexplicable reason... *cough*.
> 
> Still happens occasionally on weekends.
> 

Good, I'm not going mad(der).

-- 

Regards
     Stephen

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I'm with clipka - I think your code must be missing a ) or a } or an #end or
something.  It's always useful to stick a few #debug statements in to see what's
going on.

(I've thought a lot about tracking the "depth" of parts of scene code, and if a
global variable were defined, then every time one opens up a deeper level (#if,
#while, #for, #macro, etc) one increments that variable, then decrements it when
exiting, perhaps that would help narrow down WHERE a particular error was
occurring, and give a clue as to HOW it was being triggered.)


"cbpypov" <nomail@nomail> wrote:
New (especially foreign [for me in this case]) sayings are
> always great. How many chances do you have in a lifetime to use this one (my
> pleasure to give you one of these possibilities ;) )?

Well I was trying to remember the guy's name, and the first thing that popped
into my mind was Rumpelstiltskin - but that wasn't right.

It gets interesting when you check out Wikipedia:
"Rumpelstiltskin is a fairytale popularly associated with Germany (where he is
known as Rumpelstilzchen). The tale was one collected by the Brothers Grimm in
the 1812 edition of Children's and Household Tales. According to researchers at
Durham University and the Universidade Nova de Lisboa, the story originated
around 4,000 years ago.[1][2]"


> However, when it comes to reading the (comparatively unimportant) header info,
> not a single line slips through your eyes :D

Well, as Doctor Who fan, I'm especialy sensitive to these temporal anomalies. ;)



> Ah, I see: I've put the publication link in the header (which you've read
> thoroughly :) ). I had not seen this paper before, thank you for the hint.

Well, for a further coincidence, the LED light in my bedroom must be a photonic
crystal, because when I went to turn it on this morning, the globe was filled
with water (we're having a storm) - it looks like it's operating in "leaky mode"

:D


> Best, Carlo

Thanks  :)

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To all of you:

THIS IS THE WRONG ERROR CODE, PLEASE IGNORE:
> >
> >     File 'phc_and_excitation_enhancement.pov' line 372: Parse Error: Expected
> >      'numeric expression', undeclared identifier 'Trans_vec' found instead
> >     Fatal error in parser: Cannot parse input.
> >     Render failed
>
> Smells like malformed scene code to me. Some missing `#end`, misplaced
> loop statement, or something along those lines.

THE CORRECT ERROR CODE:

  Internal limit exceeded in FixedSimpleVector
  ==== [Rendering...] ========================================================
  Fatal error in renderer: A POV-Ray internal nesting limit was reached.
  Render failed

It occurs only if the number of emitters is too large and when their auras
are rendered as a media statements in a large contain (called Alain's version by
me, above).

Still any hints on this appreciated :)

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Am 30.10.2017 um 13:31 schrieb cbpypov:

> THE CORRECT ERROR CODE:
> 
>   Internal limit exceeded in FixedSimpleVector
>   ==== [Rendering...] ========================================================
>   Fatal error in renderer: A POV-Ray internal nesting limit was reached.
>   Render failed
> 
> It occurs only if the number of emitters is too large and when their auras
> are rendered as a media statements in a large contain (called Alain's version by
> me, above).
> 
> Still any hints on this appreciated :)

Ah, yes, that makes a lot more sense (to the trained eye, at any rate).

While nowadays (v3.7 and later) most of POV-Ray uses dynamically-sized
data structures for lists and stuff, there is a handful of data
structures that are still fixed in size, as we haven't managed yet to
get rid of them without degrading performance.

The size of those data structures was chosen quite arbitrarily, with the
corresponding constants being defined in `source/core/configcore.h`.
Search for `FixedSimpleVector Sizes`.

No way around this except re-compiling POV-Ray with tweaked constant sizes.

Post a reply to this message

>
> No way around this except re-compiling POV-Ray with tweaked constant sizes.
>

OR Python :)

-----------------------------------------------------------------------------

Hey all,

sorry for the delay. I see there are no more suggestions regarding the residual
problems :) That's ... exactly what I found out too: these problems might not
(or hardly) be addressable in POV-Ray. But in Python :)

However, it does not mean that they cannot be solved _at all_, right?

So I did. Somehow I was blind and kept on tweaking my POV-code over and over,
but the problem was simply that the data defined in this hexagonal unit cell.
Which is just unfavorable for the POV-rendering.

What I did (in very brief):

I threw away field values which are exactly 0.0, so that I have the field in
really only the hexagonal unit cell. Afterwards, I tiled the data on a hexagonal
grid and used an interpolator to achieve a regularly gridded data set in the
whole range where I wanted to show the field. Then I exported it to three
df3-files (for each of R, G, B) as before.

The same was done for the emitters: I randomly chose the emitter locations in
the part of the unit cell I desired, tiling them and choosing new ones on every
tile. So this gives me a completely random distribution of emitters in the whole
data range, -- not like before a repetitive pattern of randomly chosen emitters
in the unit cell only.

From these coordinates, I calculated the density using a sum of the spherical
exponential decays for _each_ emitter directly in Python as well. So this is
just another df3 for the emitter auras, i.e. intensities giving me a fourth
medium in the POV-scene.

So I end up with only 4 df3 files, circumventing any of the low-level problems
in POV-Ray, -- while still allowing to set the aura and field brightness in the
scene independently. Moreover, the auras and the field can be interpolated in
the POV-scene in one step!

As a result, I only have a minimal number of well-defined input files, the code
is much more elegant, and all the problems are gone :)

There is a small, low-Q render in the attachment. I'll post the complete code,
input files and high-Q render once I'm done. The attached render has some shifts
between the auras and the emitter spheres because it uses a very coarse data set
(will be gone when the fine one is ready: the interpolation and density
computation takes some time... it's running). The field cut-off at the front is
because I used a small data set for testing.

IMPORTANT
---------

I AM REALLY GRATEFUL, for all your help and for sharing this knowledge with me!
I'd like to include those of you who contributed so much of their free time into
my thesis acknowledgments. Could you elaborate on how (and if) you want to
appear there? :)

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Attachments:
Download '20171101_scene1_lowq.png' (340 KB)

Preview of image '20171101_scene1_lowq.png'

My god, it's full of stars.

I'm glad you got it to your satisfaction which is good enough for me.



-- 

Regards
     Stephen

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Am 31.10.2017 um 21:44 schrieb cbpypov:

> I AM REALLY GRATEFUL, for all your help and for sharing this knowledge with me!
> I'd like to include those of you who contributed so much of their free time into
> my thesis acknowledgments. Could you elaborate on how (and if) you want to
> appear there? :)

How about mentioning "the POV-Ray community"?

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clipka <ano### [at] anonymousorg> wrote:

> How about mentioning "the POV-Ray community"?

or "the active users and developers at news.povray.org"   :)

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"Bald Eagle" <cre### [at] netscapenet> wrote:
> clipka <ano### [at] anonymousorg> wrote:
>
> > How about mentioning "the POV-Ray community"?
>
> or "the active users and developers at news.povray.org"   :)

I like that and will do it exactly that way :)

And here, -- as promised --, the complete code including (much more coarse) data
files for a complete render. It includes the bash-script that I use to generate
the different scenes. (I'm already playing with an animation and it looks really
nice :) )

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Attachments:
Download 'phc_and_excitation_enhancement.zip' (97 KB)

.... and a high-Q render.

See you soon and keep on like that!

Best,
Carlo

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Attachments:
Download '20171101_scene1_highq.png' (3088 KB)

Preview of image '20171101_scene1_highq.png'