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22 May 2024 08:27:53 EDT (-0400)
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From: Bald Eagle
Subject: Re: Oscilloscope
Date: 6 Feb 2023 13:30:00
Message: <web.63e146b833e903b1f9dae3025979125@news.povray.org>
William F Pokorny <ano### [at] anonymousorg> wrote:

> I too forgot about the no_radiosity keyword! I believe this the better
> approach to make the screen invisible to radiosity rays, but as you said
> it would need to be built in such a way all the glowing bits are
> represented as stand alone objects such that the keyword could be used.

I professional photography, they will use an-off camera reflector for
fill-lighting.

Can the reverse be done?  What if you shielded the screen with a black square or
mesh, and used no_object so that it wasn't visible?  Or something semi-opaque
that would still allow lighting, like a diffuser on a light-bulb?

This is a beautiful scope model, and the animated lissajous curves are nice  :)

- BE


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From: m@b
Subject: Re: Oscilloscope
Date: 7 Feb 2023 03:49:02
Message: <63e2107e@news.povray.org>
Thanks for those. The low_error_factor was the one that shows the best 
improvement.
If I throw everything at it the dithering goes away, although the render 
time is rather long at 21 min/frame.

Here are my "Everything" settings:

     radiosity {
     pretrace_start 0.04
     pretrace_end 0.00125
     minimum_reuse 0.001
     count 700 25000
     recursion_limit 2
     nearest_count 20, 7
     error_bound 0.44
     low_error_factor 0.05
     }



On 06/02/2023 10:22 PM, Alain Martel wrote:
> Le 2023-02-06 à 02:41, m@b a écrit :
>> This helped, the blotchiness is acceptable for a still image but still 
>> jumpy in animation.
>>
>> Raising the 'scope - yes, good point.
>>
> 
> Try those one by one :
> Slightly increasing error_bound (this will make the rendering go a 
> little bit faster)
> (your actual value is 0.35)
> error_bound 0.37
> error_bound 0.4
> error_bound 0.44
> 
> Increase count
> count 450 12347
> count 700 25000
> nearest_count 20 7
> 
> Set minimum_reuse slightly smaller than pretrace_end such as :
> (default is minimum_reuse 0.015 for a default pretrace_end of 0.04)
> pretrace_end 0.0025
> minimum_reuse 0.002
> 
> pretrace_end 0.00125
> minimum_reuse 0.001
> 
> Set low_error_factor to a smaller value (default is 0.5)
> low_error_factor 0.3
> low_error_factor 0.1
> 
>


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Attachments:
Download 'everything.mp4.dat' (54 KB) Download 'low_error_factor 0.05 .mp4.dat' (54 KB) Download 'low_error_factor 0.1 .mp4.dat' (54 KB) Download 'low_error_factor 0.3.mp4.dat' (54 KB) Download 'pretrace_end 0.00125 .mp4.dat' (56 KB) Download 'pretrace_end 0.0025.mp4.dat' (55 KB) Download 'count 700 25000 nearest 20 7.mp4.dat' (54 KB) Download 'count 450 12347.mp4.dat' (55 KB) Download 'error_bound 0.4.mp4.dat' (55 KB) Download 'error_bound 0.37.mp4.dat' (55 KB)

From: m@b
Subject: Re: Oscilloscope
Date: 7 Feb 2023 03:53:17
Message: <63e2117d@news.povray.org>
Some reason the mp3s did not attach. Try again:


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Attachments:
Download 'low_error_factor 0.05 .mp4.dat' (54 KB) Download 'low_error_factor 0.1 .mp4.dat' (54 KB) Download 'low_error_factor 0.3.mp4.dat' (54 KB) Download 'pretrace_end 0.00125 .mp4.dat' (56 KB) Download 'pretrace_end 0.0025.mp4.dat' (55 KB) Download 'count 700 25000 nearest 20 7.mp4.dat' (54 KB) Download 'count 450 12347.mp4.dat' (55 KB) Download 'error_bound 0.4.mp4.dat' (55 KB) Download 'error_bound 0.37.mp4.dat' (55 KB)

From: m@b
Subject: Re: Oscilloscope
Date: 7 Feb 2023 03:54:49
Message: <63e211d9@news.povray.org>
On 07/02/2023 4:53 PM, m@b wrote:
> Some reason the mp3s did not attach. Try again:
Hmm - It only lets me attach one mp3????


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Attachments:
Download 'pretrace_end 0.00125 .mp4.dat' (56 KB) Download 'pretrace_end 0.0025.mp4.dat' (55 KB) Download 'count 700 25000 nearest 20 7.mp4.dat' (54 KB) Download 'count 450 12347.mp4.dat' (55 KB) Download 'error_bound 0.4.mp4.dat' (55 KB) Download 'error_bound 0.37.mp4.dat' (55 KB)

From: m@b
Subject: Re: Oscilloscope
Date: 7 Feb 2023 03:55:59
Message: <63e2121f@news.povray.org>
On 07/02/2023 4:54 PM, m@b wrote:
> On 07/02/2023 4:53 PM, m@b wrote:
>> Some reason the mp3s did not attach. Try again:
> Hmm - It only lets me attach one mp3????
They are only small files!


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Attachments:
Download 'count 700 25000 nearest 20 7.mp4.dat' (54 KB) Download 'count 450 12347.mp4.dat' (55 KB) Download 'error_bound 0.4.mp4.dat' (55 KB) Download 'error_bound 0.37.mp4.dat' (55 KB)

From: m@b
Subject: Re: Oscilloscope
Date: 7 Feb 2023 03:57:45
Message: <63e21289$1@news.povray.org>
On 07/02/2023 4:55 PM, m@b wrote:
> On 07/02/2023 4:54 PM, m@b wrote:
>> On 07/02/2023 4:53 PM, m@b wrote:
>>> Some reason the mp3s did not attach. Try again:
>> Hmm - It only lets me attach one mp3????
> They are only small files!
One more.


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Attachments:
Download 'error_bound 0.4.mp4.dat' (55 KB)

From: Kenneth
Subject: Re: Oscilloscope
Date: 7 Feb 2023 04:45:00
Message: <web.63e21cb733e903b9b4924336e066e29@news.povray.org>
"Bald Eagle" <cre### [at] netscapenet> wrote:
>
> What if you shielded the screen with a black square or
> mesh, and used no_object so that it wasn't visible?

That idea intrigued me, so I just spent several interesting hours(!) testing it
in all sorts of ways. I thought the answer would be a simple and obvious YES--
but it turned out to be a deceptively complex question. ;-)

The short answer is... YES and NO. My test scene is different from m@b's of
course, but I'll use an analogy to his oscilloscope. Yes, the no_image black
square does block radiosity light that's emanating from the screen's waveform--
but it does not eliminate the animation flicker caused by the waveform's
movement...even if the screen 'object' (assuming it's a separate object) has the
no_radiosity flag. That's rather strange, IMO. It's as if the black object is
blocking the light in one paradigm, but allowing the light to pass in another.

To put it another way: If the entire oscilloscope used the no_radiosity flag,
and was totally enclosed in a big black box that's made no_image-- the moving
waveform would still cause flicker throughout the scene.

There seems to be a simple 'rule of thumb' here: If the camera can 'see' any
movement in the scene at all, there is going to be flicker. (Saving and
reloading rad data from frame to frame can certainly minimize that, like m@b
finally used. Assuming that there are no actual moving OBJECTS in the scene.)

But this no-radiosity behavior seems odd. My current grasp of the docs'
description is that it should not only allow radiosity rays to pass through an
object as if it was invisible, but also to stop an object from *producing*
radiosity light. I'm obviously wrong about that last bit. The other surprise is
that a no_rad object still 'collects' rad-light patches from other objects (even
though it's supposed to be 'invisible' to them.) That may or may not be logical
and consistent, I don't know.


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From: Kenneth
Subject: Re: Oscilloscope
Date: 7 Feb 2023 05:00:00
Message: <web.63e2209933e903b9b4924336e066e29@news.povray.org>
"m@b" <sai### [at] googlemailcom> wrote:

> One more.

That one looks like only a single animation frame came through :-(


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From: Kenneth
Subject: Re: Oscilloscope
Date: 7 Feb 2023 06:25:00
Message: <web.63e234e133e903b9b4924336e066e29@news.povray.org>
"Kenneth" <kdw### [at] gmailcom> wrote:
> "Bald Eagle" <cre### [at] netscapenet> wrote:
> >
> > What if you shielded the screen with a black square or
> > mesh, and used no_object so that it wasn't visible?
>
> That idea intrigued me, so I just spent several interesting hours(!) testing it
> in all sorts of ways...

Forgot to mention that I went back to using a single thread for the tests, to
eliminate most of the scene's other radiosity flicker.

>
> But this no-radiosity behavior seems odd. My current grasp of the docs'
> description is that it should...stop an object from *producing*
> radiosity light. I'm obviously wrong about that...

Sorry, that was a bit confused. What I meant to say was, it DOES keep the object
from emitting radiosity light-- but it does not stop the same 'non-light' from
causing animation flicker in the rest of the scene's radiosity when the object
has a moving pigment, like the oscilloscope screen. That's the paradox.


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From: Alain Martel
Subject: Re: Oscilloscope
Date: 7 Feb 2023 10:51:33
Message: <63e27385$1@news.povray.org>
Le 2023-02-07 à 03:54, m@b a écrit :
> On 07/02/2023 4:53 PM, m@b wrote:
>> Some reason the mp3s did not attach. Try again:
> Hmm - It only lets me attach one mp3????

The first one showed all 10 MP4s, then,  9, 6, 4 and 1.
The problem is that none show anything more than a black frame.


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