"Bill Pragnell" <bil### [at] hotmailcom> wrote:
> "Mr" <nomail@nomail> wrote:
> > Eyecandy!
> > I would be interested in your radiosity settings and render times, maybe even in
> > some kind of tutorial? Because the geometry looks challenging to that regard.
>
> I use UberPOV almost exclusively these days, which has an unbiased radiosity
> algorithm. This is a more brute-force approach to global illumination, but I
> find it produces much better results at lower counts than regular radiosity - no
> patchy artifacts, and no need for fine-tuning. The tradeoff is noisiness in
> unlit areas, which can be much reduced by cranking up the count for final
> renders. I've never been able to completely beat the dreaded radiosity artifacts
> for regular radiosity except under the most ideal conditions.
>
> UberPOV was originally a blue-sky testbed for new features, but is somewhat
> stalled at present. This means it's stuck on v3.7.0, and I miss out on the newer
> features in v3.8+. However, I'm told there are plans to incorporate this
> radiosity algorithm in base POV-Ray eventually...
>
> This image rendered in about 20-30 minutes on a 2012 dual-core laptop (I don't
> have the exact time to hand!)
>
> Bill

Thanks ! These are very convincing numbers... and indeed I for one wouldn't have
managed to have any patch-free result at that speed. I hope any expert would be
able to pick up that challenge and prove there is actually some alternative for
such solutions when using official POV master ?

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"Mr" <nomail@nomail> wrote:
> Thanks ! These are very convincing numbers... and indeed I for one wouldn't have
> managed to have any patch-free result at that speed.

Forgot to mention, the radiosity count value was 100.

It's worth pointing out that there's absolutely nothing fancy in this scene,
everything's just flat colours, and I've kept recursion_limit at 1, which means
only directly-lit or emissive areas contribute to the radiosity lighting.
There's also a bit of geometry optimisation - everything is either boxes or
meshes, which render very quickly, except for the CSG in the roofs, which I've
bounded manually.

A high-quality render with a high radiosity count, complex textures,
reflections/glass and media would obviously be somewhat slower!

Bill

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"Bill Pragnell" <bil### [at] hotmailcom> wrote:
> Following Thomas' comments about the stairs, plus my own dissatisfactions, I
> have made some minor improvements...

This is a fascinating project to watch as it develops; the results are really
astounding. I'm sorry that I did not comment earlier, I was wrapped up in my own
POV-Ray chores, ha; but I went back and read all of the discussions starting
with your original post of Nov 9.

It all looks impossibly complex-- and quite beautiful. Thanks for sharing the
various renders and for explaining the nuts-and-bolts of how it was done.

Looking forward to seeing more!

-----
In one of your earlier threads/posts, you mentioned the possibility of using a
'radiosity-only' light_source (a feature (?) in UBER POV), for adding additional
fill light(?) to some of the darker recesses of your construction. Even if I'm
wrong about your meaning, it sounds like an interesting feature to contemplate:
A light_source that does not directly light-up an object surface, but does allow
the object to emit radiosity bounce-lighting (from that light) to other objects.

Doing some testing, I see that the same effect can be achieved in 'classic'
POV-Ray by using two identical objects for the 'main' object (one with
no_radiosity, one with no_image), perhaps in combination with an optional
light_group. The no_radiosity version is lit directly by the light; the no_image
version-- perhaps with a different finish{diffuse...} value-- casts the
light-produced rad onto other objects. (This may even be a way of 'tuning' the
rad lighting's cascading intensity from object to object. It would all be a
rather complicated construction, of course.)

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"Kenneth" <kdw### [at] gmailcom> wrote:
> It all looks impossibly complex-- and quite beautiful. Thanks for sharing the
> various renders and for explaining the nuts-and-bolts of how it was done.

Thanks for the interest! Feedback is a real motivator - if people are interested
in more, I'm more likely to take it further. Not that I'm not interested in it
for my own sake of course, but real life is so tiring :)

> In one of your earlier threads/posts, you mentioned the possibility of using a
> 'radiosity-only' light_source (a feature (?) in UBER POV), for adding
> additional fill light(?) to some of the darker recesses of your construction.
> Even if I'm wrong about your meaning, it sounds like an interesting feature to
> contemplate: A light_source that does not directly light-up an object surface,
> but does allow the object to emit radiosity bounce-lighting (from that light)
> to other objects.

I think what I meant was just to use radiosity to provide all the light, i.e.
have emissive blobs (maybe hidden using no_image) rather than light sources.
This isn't an UberPOV-only option, it just works better than in base POV-Ray
because I don't have to worry about radiosity artifacts.

There was an UberPOV-only option - use lots of distance-faded light_sources.
This can also be done in base POV-Ray of course, but UberPOV allows such
light_sources to be ignored over a certain distance away, which turns a dog-slow
render into something feasible.

Bill

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"Kenneth" <kdw### [at] gmailcom> wrote:
> possibility of using a
> 'radiosity-only' light_source
> to some of the darker recesses of your construction

Then there's this - see attached...

Happily this rendered in <10 mins!

Bill

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Attachments:
Download 'autobuild_dark.jpg' (112 KB)

Preview of image 'autobuild_dark.jpg'

Op 16/12/2021 om 17:19 schreef Bill Pragnell:
> "Kenneth" <kdw### [at] gmailcom> wrote:
>> It all looks impossibly complex-- and quite beautiful. Thanks for sharing the
>> various renders and for explaining the nuts-and-bolts of how it was done.
> 
> Thanks for the interest! Feedback is a real motivator - if people are interested
> in more, I'm more likely to take it further. Not that I'm not interested in it
> for my own sake of course, but real life is so tiring :)
> 
Absolutely right! And this is an inspiring project.

>> In one of your earlier threads/posts, you mentioned the possibility of using a
>> 'radiosity-only' light_source (a feature (?) in UBER POV), for adding
>> additional fill light(?) to some of the darker recesses of your construction.
>> Even if I'm wrong about your meaning, it sounds like an interesting feature to
>> contemplate: A light_source that does not directly light-up an object surface,
>> but does allow the object to emit radiosity bounce-lighting (from that light)
>> to other objects.
> 
> I think what I meant was just to use radiosity to provide all the light, i.e.
> have emissive blobs (maybe hidden using no_image) rather than light sources.
> This isn't an UberPOV-only option, it just works better than in base POV-Ray
> because I don't have to worry about radiosity artifacts.
> 
It has been some while since I last used UberPOV, in fact since I 
switched to the successive v3.8 betas, and I guess those would also 
avoid radiosity artefacts, especially when using stochastic render? I am 
mumbling away, really, and it should be tested of course.

> There was an UberPOV-only option - use lots of distance-faded light_sources.
> This can also be done in base POV-Ray of course, but UberPOV allows such
> light_sources to be ignored over a certain distance away, which turns a dog-slow
> render into something feasible.
> 
Hmm... didn't remember that one.

-- 
Thomas

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Il 16/12/2021 20:19, Bill Pragnell ha scritto:
 > "Kenneth" <kdw### [at] gmailcom> wrote:
 >> possibility of using a
 >> 'radiosity-only' light_source
 >> to some of the darker recesses of your construction
 >
 > Then there's this - see attached...
 >
 > Happily this rendered in <10 mins!
 >
 > Bill

Mmm... with a red or blue background light the image could became scary...

Paolo

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Thomas de Groot <tho### [at] degrootorg> wrote:
> It has been some while since I last used UberPOV, in fact since I
> switched to the successive v3.8 betas, and I guess those would also
> avoid radiosity artefacts, especially when using stochastic render?

I believe the unbiased radiosity implementation is UberPOV-only so far; the
'stochastic' nature of 3.8 refers to blur and antialiasing supersampling.
Radiosity sampling is an entirely different mechanism, and the associated
artefacts are larger-scale lighting effects.

PS as far as I know! Any experts, please correct me :)

Bill

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"Bill Pragnell" <bil### [at] hotmailcom> wrote:
> "Kenneth" <kdw### [at] gmailcom> wrote:
> > possibility of using a
> > 'radiosity-only' light_source
> > to some of the darker recesses of your construction
>
> Then there's this - see attached...
>
> Happily this rendered in <10 mins!
>
> Bill

I really really like that image. :-) A Dyson sphere in Escher's Universe...
What about adding a bit of atmosphere to catch the light rays escaping from that
structure ?
Can't wait to see your next renders on that project. As Dave Blandston said,
it's going to become a POV-Ray classic !

Pascal

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Paolo Gibellini <p.g### [at] gmailcom> wrote:
> Il 16/12/2021 20:19, Bill Pragnell ha scritto:
> >
>  >
>  > Then there's this - see attached...
>  >
>  > Happily this rendered in <10 mins!
>  >
>
> Mmm... with a red or blue background light the image could became scary...
>

And if the rad-emitting object were to be made no_image (and possibly smaller in
size), the effect would be quite interesting and even scarier! In the current
render, it looks like a big white sphere; if it's made invisible, then only its
rad-lighting effect will show up.

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