RE:
Subject: Laser Light Source with Photons...
Date: 13 Jul 2008 04:55:00
Message: <web.487989b0797036a91a8107a20@news.povray.org>


re: Blue Herrin's code:


Subject: Re: Laser Light Source with Photons...
Date: 18 Jul 2008 14:53:33
Message: <4880ae6d$1@news.povray.org>

basically rgbft to reflector

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I wonder if another program, not POV, was used here:
http://www.imagico.de/pov/meta/block_neg.jpg


Lighting this scene for shadows inside this media filled sphere presents a
number of problems.

Is there a way?

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Download 'lasereflect6.png' (6 KB)

Preview of image 'lasereflect6.png'

"alphaQuad" <alp### [at] earthlinknet> wrote in message 
news:web.4881fcd12dc5bc4e68c5136d0@news.povray.org...
>I wonder if another program, not POV, was used here:
> http://www.imagico.de/pov/meta/block_neg.jpg
>
>
> Lighting this scene for shadows inside this media filled sphere presents a
> number of problems.

yes I've seen this as well .... I wanted to throw some light (is there a pun 
there?) onto the target so I added another light source (media_interaction 
off) then included it in a light_group with the target as the lone member of 
that light_group (global_lights off). the target just has pigment no finish 
block (reflection is 0 unless otherwise specified right?) yet it looks like 
light is indeed making it off the target enough to fire up the media. the 
light_group light source is parallel and has point_at set to the center of 
the target. pardon the spotty nature of the media, I have samples reduced by 
a factor of ten while testing, otherwise it takes about an hour for each 
test.

a difficult lighting challenge indeed.

Jim

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"Jim Holsenback" <jho### [at] hotmailcom> wrote:
> "alphaQuad" <alp### [at] earthlinknet> wrote in message
> news:web.4881fcd12dc5bc4e68c5136d0@news.povray.org...
> >I wonder if another program, not POV, was used here:
> > http://www.imagico.de/pov/meta/block_neg.jpg
> >
> >
> > Lighting this scene for shadows inside this media filled sphere presents a
> > number of problems.
>
> yes I've seen this as well .... I wanted to throw some light (is there a pun
> there?) onto the target so I added another light source (media_interaction
> off) then included it in a light_group with the target as the lone member of
> that light_group (global_lights off). the target just has pigment no finish
> block (reflection is 0 unless otherwise specified right?) yet it looks like
> light is indeed making it off the target enough to fire up the media. the
> light_group light source is parallel and has point_at set to the center of
> the target. pardon the spotty nature of the media, I have samples reduced by
> a factor of ten while testing, otherwise it takes about an hour for each
> test.
>
> a difficult lighting challenge indeed.
>
> Jim

"a difficult lighting challenge indeed" ONLY when you cant think of what to do,
as was my case. I saw "media_interaction off", doh! Seen it before but didnt
think of it. this one in only 20 minutes, no AA.

code available if anyone has computer muscle and wants to play.

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Attachments:
Download 'lasereflect_1.png' (52 KB)

Preview of image 'lasereflect_1.png'

"Jim Holsenback" <jho### [at] hotmailcom> wrote:

> a difficult lighting challenge indeed.
>
> Jim

I should have said thanks, you made me go back to it, or it could have died.
aQ

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somethings says I need to calc prism reflection angles.

anyone need a prism?

#declare _prism = prism {
linear_sweep
bezier_spline
0.44, //top
0.0, //bottom
12 ,
<0.22,0>,<-0.22,0>,<0.22,0>,<-0.22,0>,
<-0.22,0>,<0.0,0.38106>,<-0.22,0>,<0.0,0.38106>,
<0.0,0.38106>,<0.22,0>,<0.0,0.38106>,<0.22,0>
}

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Attachments:
Download 'lasereflect_02.png' (44 KB)

Preview of image 'lasereflect_02.png'

current prism material cuts light by 50%
concave reflectors dont focus, small diameter light at least.
convex lenses focus

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Download 'lasereflect03.png' (206 KB)

Preview of image 'lasereflect03.png'

"alphaQuad" <alp### [at] earthlinknet> wrote in message 
news:web.488563ab2dc5bc4e358e2dfa0@news.povray.org...
> current prism material cuts light by 50%
> concave reflectors dont focus, small diameter light at least.
> convex lenses focus

nice job ..... this one might be a nice example scene to include in 3.7 
examples

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"Jim Holsenback" <jho### [at] hotmailcom> wrote:
> "alphaQuad" <alp### [at] earthlinknet> wrote in message
> news:web.488563ab2dc5bc4e358e2dfa0@news.povray.org...
> > current prism material cuts light by 50%
> > concave reflectors dont focus, small diameter light at least.
> > convex lenses focus
>
> nice job ..... this one might be a nice example scene to include in 3.7
> examples


Thank you.

Concave reflectors focus.
(was a CSG fopah I made)

flat surfaces produce photon flotsam

next image should be sweet, 18% complete and 14 minutes into it, thats good.
(Its the 3 hour renders that make me blue)

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"Jim Holsenback" <jho### [at] hotmailcom> wrote:
> nice job ..... this one might be a nice example scene to include in 3.7
> examples

what this really needs, I think is possible  ...

not just photon use on/off, but at least 3 options should be devised.

off
low-quality preview ie. fast
quality slow-render


/*
photons {
  spacing <photon_spacing> | count <photons_to_shoot>

  [gather <min_gather>, <max_gather>]
  [media <max_steps> [,<factor>]]
  [jitter <jitter_amount>]
  [max_trace_level <photon_trace_level>]
  [adc_bailout <photon_adc_bailout>]
  [save_file "filename" | load_file "filename"]
  [autostop <autostop_fraction>]
  [expand_thresholds <percent_increase>, <expand_min>]
  [radius <gather_radius>,<multiplier>,
          <gather_radius_media>,<multiplier>]
}
*/

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