Well this discussion is completely over my head, but looks good anyway!
Wish MY office was so neat. . .


-Dayv
"Jaime Vives Piqueres" <jai### [at] ignoranciaorg> wrote in message
news:3c24b720@news.povray.org...
> Hi Hugo:
>
> > I am very impressed by this! Both the lighting and modelling. There are
> > many well defined objects. I suppose you've made them over the
years..Your
> > homepage has many objects too.. great stuff!  :o)  But 30 hours
rendertime
> > is scaring, a little..
>
>   Thanks! Yes, most of the objects are "stock" objects, some other are
> still placeholders. And 30h is very fast, really. Without saved radiosity
> data it would take at least a 50% more. At first, it was even more slow
> because I've put the lights inside CSG diference objects. Now, with
unions,
> it renders much faster (I must remember this).
>
> > Will you explain the lighting technique for us, once
> > you are satisfied with it?
>
>   Yes, it is an include file with a very short macro and some constants.
It
> is mostly based on using very strong intensities and very short
> attenuation.  Not a try to get something "physically correct", but
> arbitrarily based on real color and lumens data to mantain a realistic
> relation between diferent lights in the same scene. Basically, you call
the
> macro this way:
>
>   lamplight(COLOR_INCANDESCENT,LUMENS_INCANDESCENT_60W)
>
>   or
>
>   lamplight(COLOR_FLUOR_UNIVERSAL_WHITE,LUMENS_FLUOR_18W)
>
>   and it returns a light_source properly adjusted, taking into account two
> global constants previously defined: REFERENCE_WHITE and
> MAXIMUM_LUMENS_ALLOWED. It's up to you to build the light container (bulb,
> lamp, etc...).
>
>   Pretty simple in code, but I expended some months understanding some
> concepts about light. I will show it soon...
>
> > Did you find out why radiosity artifacts were
> > gone when using a saved rad file?
>
>   Oh! Yes... I followed the advice from Kari of using this setup for the
> load scene:
>
>   radiosity{
>     pretrace_start 1 pretrace_end 1
>     always_sample off
>     load "rad_file"
>   }
>
>   But as this is using default error bound, wich was greater than the one
I
> used for the saved data, the final render "smoothed" the artifacts. Seems
> that when loading rad data error_bound is taken into account. For ideal
> results with high quality settings you should use also the same error
bound
> as in the "dummy" render. But it also helps to get "quick-but-clean"
> results with radiosity.
>
> > Does it really work to use a rad file
> > taken from a lower-resolution image?
>
>   I tried it with the "official" cornell-box scene done by Kari (very
> good!), and it shows very similar results with saved data from a previous
> render at 1/3 resolution. Substracting the original image from the
"tricky"
> one shows an almost black image (I had to increase brightness to see the
> diferenced zones). Of course, the original image is better, much more
> smooth, but this is still a great trick for lazy people like me (or
you...;)
>
>   Bye!
>
> --
> Jaime Vives Piqueres
>
> La Persistencia de la Ignorancia
> http://www.ignorancia.org

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