I saw Kari Kivisalo's suggestions to Tim Nikias on realistic light fading and
gave it a quick go. I set up two identical rooms and a doorway. In one room, a
light was placed slightly lower than the ceiling, but higher than the doorway
height. This light was square and used 25 spotlights are per Kari's suggestions.
I used radiostity with a recursion limit of 5 (probably a little excessive) and
here are the results.
    One is a shot from within the lit room. The other is the same shot, but from
within the unlit room. The imperfect soft shadows are caused by the set up of the
pseudo area-light. No post process was performed.
    I suggest we call these wonderful lights Kari-lights in honour of their
inventor :-)

MJL

--
light_source{9*(y#macro A(H,B,R,T)prism{0,1H+4,0u*9,9v*9,0#local I=1;#while(I<H)
#local V=asc(substr(B,I,1))-33;<div(V,10)mod(V,10)>#local I=I+1;#end pigment{rgb
y}rotate-<90,R>translate-T}#end-z)rgb 9}A(14",6;MWmhryXN3,"60<15,0,8>)box{-99(x+
z)*99pigment{rgb 1}}fog{distance 11}camera{location(y-z)*25look_at 0}A(8"6hiAG=6
"-60x*-10)A(16"/.@VZno=<PLA89/"0x*5) // MJL

Post a reply to this message

Attachments:
Download 'rad_room_b.jpg' (20 KB) Download 'rad_room_a.jpg' (17 KB)

Preview of image 'rad_room_b.jpg'

Preview of image 'rad_room_a.jpg'

Great!

Pretty cool!

I like it a lot!


Best regards

Post a reply to this message

Lighting is great as you say, but the door way is far too wide. 

--
%HAV-A-NICEDAY                    email mailto:ste### [at] zeroppsuklinuxnet
Steve                                web http://www.zeropps.uklinux.net/
                                             or http://start.at/zero-pps
 11:33pm  up 106 days, 15:22,  1 user,  load average: 1.06, 1.11, 1.11

Post a reply to this message

JPGargoyle wrote:

> Great!
>
> Pretty cool!
>
> I like it a lot!
>
> Best regards

Thanks!

--
light_source{9*(y#macro A(H,B,R,T)prism{0,1H+4,0u*9,9v*9,0#local I=1;#while(I<H)
#local V=asc(substr(B,I,1))-33;<div(V,10)mod(V,10)>#local I=I+1;#end pigment{rgb
y}rotate-<90,R>translate-T}#end-z)rgb 9}A(14",6;MWmhryXN3,"60<15,0,8>)box{-99(x+
z)*99pigment{rgb 1}}fog{distance 11}camera{location(y-z)*25look_at 0}A(8"6hiAG=6
"-60x*-10)A(16"/.@VZno=<PLA89/"0x*5) // MJL

Post a reply to this message

Steve wrote:

> Lighting is great as you say, but the door way is far too wide.

Thanks! Yes, the door is too wide, but you can't expect perfect geometry from a
10 minute "let's see how this turns out" sort of job.

--
light_source{9*(y#macro A(H,B,R,T)prism{0,1H+4,0u*9,9v*9,0#local I=1;#while(I<H)
#local V=asc(substr(B,I,1))-33;<div(V,10)mod(V,10)>#local I=I+1;#end pigment{rgb
y}rotate-<90,R>translate-T}#end-z)rgb 9}A(14",6;MWmhryXN3,"60<15,0,8>)box{-99(x+
z)*99pigment{rgb 1}}fog{distance 11}camera{location(y-z)*25look_at 0}A(8"6hiAG=6
"-60x*-10)A(16"/.@VZno=<PLA89/"0x*5) // MJL

Post a reply to this message

Mark James Lewin wrote:
>
> This light was square and used 25 spotlights are per Kari's suggestions.

For this one area_light D*x, D*z, 5, 5 jitter adaptive 0 would be
enough. I would say that if the nearest object is within 3*fade_distance
and more accurate lighting is needed then divide the source. Try it first
with one source and see what it looks like. cornell.pov in the beta
distribution can be used to see how dividing the source affects the lighting.
The N parameter divides the source to N^2 sub sources. N=3 was mainly
used to get better lighting on the front of the tall box, the rest
of the scene is ok with 1 source. Notice how the light intensity remains
constant even when the source is divided without altering source brightness.
It's because the light source color brightness is actually brightness/area
so when a source is divided to smaller sources they still have the same
area brightness.

> I used radiostity with a recursion limit of 5 (probably a little excessive)
> and here are the results.

Looks good and a fortunate coincidence is that the scene contrast
ratio matches nicely that of a typical monitor so no post processing
is needed :) 


_____________
Kari Kivisalo

Post a reply to this message

Mark James Lewin wrote:
>
>     I suggest we call these wonderful lights Kari-lights in honour
>  of their inventor :-)

I would more like them as rayalistic lights :)


_____________
Kari Kivisalo

Post a reply to this message

Kari Kivisalo wrote:

> For this one area_light D*x, D*z, 5, 5 jitter adaptive 0 would be
> enough.

I seldom see the easy way first :-) I am still amazed at how much  indoor rad
scenes can benefit from these settings.

>
> Looks good and a fortunate coincidence is that the scene contrast
> ratio matches nicely that of a typical monitor so no post processing
> is needed :)

Thank you.

If only POV had the ability to adjust colours before they are clipped and written
to file...


--
text{ttf"timrom.ttf"concat(#local O=1;#while(O<7)chr(val(substr(concat(#local Q=
1;#while(Q<7)str(asc(substr("???<?>",Q,1))-56,0,0),#local Q=Q+1;#end""),O,2))),#
local O=O+2;#end"").1,0pigment{rgb 9}translate-<1,.3,-2>} // MJL

Post a reply to this message

Drooool!!  Now tell me the render time!

Hugo

Post a reply to this message

Mark James Lewin wrote:

>     I saw Kari Kivisalo's suggestions to Tim Nikias on realistic light

  Very good! Seems that Kari is a great inipiration for all us. I'm trying 
to finish a macro for this kind of kari-lights, which I started some months 
ago inspired by Kari comments. 

  I'm also playing with another Kari idea, and that's using spectral data 
for the lights. His original idea was to wrap spectrum pictures on a sphere 
containing the light. But that was slow, so I searched the net and found an 
algoritm to convert a sampled spectrum into rgb, and it seems to work 
pretty well for common bulbs spectrums (feven luorescents come out 
greeninsh!:). The problem is that I never seem to be even close to finish 
the macro: RL is a bit annoying sometimes... hope to have something decent 
to show soon.

-- 
Jaime Vives Piqueres

La Persistencia de la Ignorancia
http://www.ignorancia.org

Post a reply to this message