POV-Ray : Newsgroups : povray.binaries.tutorials : Where are my lights???? : Re: Where are my lights???? Server Time
24 Apr 2024 21:39:10 EDT (-0400)
  Re: Where are my lights????  
From: Bob Hughes
Date: 9 Apr 1999 01:12:33
Message: <370D7E03.31BB938A@aol.com>
Try changing all your point_at 50*y to -50*y to direct them downward
instead. They still behave like spotlights, that is, they point in one
direction; not endless cylinders going in both directions. I first
thought they did myself.
I didn't try your script out, though I believe that is the answer.


Dave Helfrich wrote:
> 
> Hi everyone!  I've been working on a scene and I'm having some trouble with
> some cylindrical lights I have in there.  In a nutshell, the scene thus far
> is a top view of a floor (made of nested discs), surrounded by a moat-like
> stone ring.  The bottom of the ring is at -3 along the y axis.  I have 6
> cylinder lights all starting at <0, 0, 82> and rotated to the places I want
> them.  The problem is that they don't light anything unless I make them
> shadowless.  I'm including 2 images... the first one rendered without the
> shadowless lights, the second with them.  I'm guessing that they're not
> lighting anything because there's something blocking them and casting a
> shadow.  I tried using the "no_shadow" option on the objects around the
> lights, but it didn't help.  What's wrong?  I'm also attaching the source.
> 
> I'd appreciate any help anyone could give me.
> 
> Thanks!
> Dave.
> 
>  [Image]
> 
>  [Image]
> 
> // Textures
> 
> // I'm using a staggared radial texture for the floor.  Here's the
> // basic texture... It will be phased later to get the circular-checkered
> // effect.  Kind of like the floor on the stage of this year's Academy Awards, but
not exactly.
> #declare rad =
> pigment {
>         radial
>         color_map {
>                 [0.5 color rgb 1.0]
>                 [0.5 color rgb 0.0]
>         }
>         frequency 10
> }
> 
> // here is the texture of the rings that will surround the floor
> // and contain the fountains, and for all the other stone in the scene as well.
> #declare stonetexture =
> texture {
>         pigment {
>                 color rgb 0.5
>         }
> 
>         normal {granite 1}
> }
> 
> // Lights... camera... ...ray trace!
> 
> light_source {
>         <0, 1000, 0>
>         color rgb 0.5//<0.17, 0.17, 0.2>
>         media_attenuation off
>         media_interaction off
>         shadowless // this is always shadowless.  just to help illuminate things
while I try
>                    // to figure out why the cylinder lights don't light
> }
> 
> // these are the cylindrical lights
> 
> light_source { // #1
>         <0, 0, 82>
>         color rgb <2.00, 0.50, 0.50>
>         cylinder
>         radius 45
>         falloff 47
>         tightness 100
>         point_at <0, 50, 82>
>         rotate <0, 270, 0>
>         media_interaction on
>         shadowless //made this shadowless for test run
> }
> 
> light_source { //#2
>         <0, 0, 82>
>         color rgb <2.00, 1.00, 0.50>
>         cylinder
>         radius 45
>         falloff 47
>         tightness 100
>         point_at <0, 50, 82>
>         rotate <0, 306, 0>
>         media_interaction on
>         shadowless //made this shadowless for test run
> }
> 
> light_source { //#3
>         <0, 0, 82>
>         color rgb <2.00, 2.00, 0.50>
>         cylinder
>         radius 45
>         falloff 47
>         tightness 100
>         point_at <0, 50, 82>
>         rotate <0, 342, 0>
>         media_interaction on
>         shadowless //made this shadowless for test run
> }
> 
> light_source { //#4
>         <0, 0, 82>
>         color rgb <0.50, 2.00, 0.50>
>         cylinder
>         radius 45
>         falloff 60
>         tightness 100
>         point_at <0, 50, 82>
>         rotate <0, 18, 0>
>         media_interaction on
>         shadowless //made this shadowless for test run
> }
> 
> light_source { //#5
>         <0, 0, 82>
>         color rgb <0.50, 0.50, 2.00>
>         cylinder
>         radius 45
>         falloff 47
>         tightness 100
>         point_at <0, 50, 82>
>         rotate <0, 54, 0>
>         media_interaction on
>         shadowless //made this shadowless for test run
> }
> 
> light_source { //#6
>         <0, 0, 82>
>         color rgb <2.00, 0.50, 2.00>
>         cylinder
>         radius 45
>         falloff 47
>         tightness 100
>         point_at <0, 50, 82>
>         rotate <0, 90, 0>
>         media_interaction on
>         shadowless //made this shadowless for test run
> }
> 
> camera {
>         location <0, 200, 0>
>         look_at <0, 0, 0>
> }
> 
> // Every scene needs some objects.
> 
> // I've never used discs before.. but layering concentric rings
> // was the only way I could think of to get the pattern I wanted.
> // The discs have the "rad" pattern, one half phase off from each other.
> 
> disc { // White circle in the center
>         <0, 0, 0>, y, 5
>         pigment {color rgb 1}
> }
> 
> disc {
>         <0, 0, 0>, y, 10, 5
>         pigment {rad}
> }
> 
> disc {
>         <0, 0, 0>, y, 15, 10
>         pigment {rad phase 0.5}
> }
> 
> disc {
>         <0, 0, 0>, y, 20, 15
>         pigment {rad}
> }
> 
> 
> disc {
>         <0, 0, 0>, y, 25, 20
>         pigment {rad phase 0.5}
> }
> 
> disc {
>         <0, 0, 0>, y, 30, 25
>         pigment {rad}
> }
> 
> disc {
>         <0, 0, 0>, y, 35, 30
>         pigment {rad phase 0.5}
> }
> 
> disc {
>         <0, 0, 0>, y, 40, 35
>         pigment {rad}
> }
> 
> disc {
>         <0, 0, 0>, y, 45, 40
>         pigment {rad phase 0.5}
> }
> 
> disc {
>         <0, 0, 0>, y, 50, 45
>         pigment {rad}
> }
> 
> disc {
>         <0, 0, 0>, y, 55, 50
>         pigment {rad phase 0.5}
> }
> 
> disc {
>         <0, 0, 0>, y, 60, 55
>         pigment {rad}
> }
> 
> disc {
>         <0, 0, 0>, y, 65, 60
>         pigment {rad phase 0.5}
> }
> 
> disc {
>         <0, 0, 0>, y, 70, 65
>         pigment {rad}
> }
> 
> 
> // this large ring immediately surrounds the floor
> difference {
>         cylinder {
>                 <0, -3, 0>, <0, 1, 0>, 72
>         }
> 
>         cylinder {
>                 <0, -3.1, 0>, <0, 1.1, 0>, 70
>         }
>         texture {stonetexture}
> }
> 
> // this outer ring will surround the floor, and the several mini-rings that will
hold the fountains.
> difference {
>         cylinder {
>                 <0, -3, 0>, <0, 1, 0>, 94
>         }
> 
>         cylinder {
>                 <0, -3.1, 0>, <0, 1.1, 0>, 92
>         }
>         texture {stonetexture}
> }
> 
> // Here's the ground that will surround the floor.  I cut out the area where
> // the floor and rings are so you don't see grass (or this really bad
> // aproximation of grass) in the bottom.
> difference {
>         plane {
>                 y, -0.5
>                 texture {
>                         pigment {
>                                 color rgb <0.25, 1.00, 0.25>
>                         }
> 
>                         normal {
>                                 average
>                                 normal_map {         // just arbitary trial & error
numbers to not
>                                         [granite 2]  // have too smooth of a ground
>                                         [bumps 1]
>                                         [dents 2]
>                                         [crackle 1]
>                                 }
>                         }
>                 }
>                 hollow
>         }
> 
>         cylinder {
>                 <0, -3.00001, 0>, <0, 1, 0>, 94
>                 texture {
>                         pigment {
>                                 color rgb 0.50
>                         }
> 
>                         normal {
>                                 average
>                                 normal_map {
>                                         [granite 2]  // more arbitrary trial & error
valuse to make
>                                         [crackle 2]  // the inside of the pools not
be smooth
>                                 }
>                         }
>                 }
>          hollow
>          no_shadow
>         }
>         hollow on
> }
> 

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