Alain <aze### [at] qwertygov> wrote:
> Danny nous apporta ses lumieres ainsi en ce 2004/05/27 23:04... :
>
> >Alain <aze### [at] qwertygov> wrote:
> >
> >
> >>Danny nous apporta ses lumieres ainsi en ce 2004/05/21 16:22... :
> >>
> >>
> >>
> >>><snip>
> >>>
> >>>
> >>>Is this cylinder light_source supposed to produce a visible light beam that
> >>>can be seen outside where it's pointing at, or is it more like a laser pen
> >>>that produces a dot on the surface it's aimed at? I tried it along with
> >>>scattering and it did nothing to get rid of the images.
> >>>Also, in order to round off the ends of my laser beam, I put some
> >>>half-spheres on either end, both filled with the same media, except the
> >>>density is spherical instead of cylindrical.  For some reason, this created
> >>>tons more problems.  When you look at the half-spheres perpendicularly,
> >>>there's no problem, but when you look at them obliquely, you get very odd
> >>>results, such as grey rings, spots, etc.  Here's what I'm doing:
> >>>
> >>>
> >>>
> >>>
> >>>
> >>Why do you use this default texture, it's the source of most of your
> >>problems
> >>
> >>
> >>
> >>>#default {
> >>>  texture {
> >>> pigment {Grey}
> >>>   finish {
> >>>    diffuse 0.6
> >>>     ior 1.5
> >>>     ambient 0.300000
> >>>     phong 0.5
> >>>     phong_size 50
> >>>}
> >>>}}
> >>>
> >>>
> >>>camera {
> >>> location <0,0.5,2>
> >>> look_at <0,0.5,0>
> >>>}
> >>>
> >>>background {color rgb <0,0,0>}
> >>>
> >>>light_source {
> >>> <-1000.000000,1000.000000,1000.000000>       //  x=-1000,y=1000,z=1000
> >>> color rgb <1.0000,1.0000,1.0000>
> >>>          }
> >>>
> >>>#declare clock1=1;
> >>>
> >>>union{
> >>>cylinder{<0,2*clock1,0>,<0,0,0>, 1                 //the laser, top right
> >>>
> >>>
> >>>from front
> >>
> >>
> >>>        texture {
> >>>   pigment { color rgbt 1}}
> >>>      interior{media{emission rgb 1
> >>>      density{ cylindrical
> >>>      color_map{[0 rgb 0][0.03 rgb <0.0004,0,0>][0.6 rgb<8,0,0>][0.98 rgb
> >>>16][1 rgb 30]} //[0 rgb 0][0.02 rgb <0.004,0,0>][0.5 rgb<4,0,0>][0.96 rgb
> >>>5][1 rgb 10]
> >>>      }}}
> >>>      hollow
> >>>      scale<0.1, 1, 0.1>
> >>>      }
> >>>
> >>>
> >>>
> >>>
> >>removing this don't change anything in your cene
> >>
> >>
> >>
> >>>difference{
> >>>sphere{<0,0,0>, 1
> >>>        texture {
> >>>   pigment { color rgbt 1}}
> >>>      interior{media{emission rgb 1
> >>>      scattering{3,1}
> >>>      density{ spherical
> >>>      color_map{[0 rgb 0][0.03 rgb <0.0004,0,0>][0.6 rgb<8,0,0>][0.98 rgb
> >>>16][1 rgb 30]}
> >>>      }}}
> >>>      hollow
> >>>      scale<0.1, 0.1, 0.1>
> >>>      translate <0,2*clock1,0>
> >>>      }
> >>>cylinder{<0,2*clock1,0>,<0,0,0>,5}
> >>>      }
> >>>
> >>>
> >>>
> >>>
> >>-----------------------------------------------------------------
> >>
> >>
> >>
> >>>difference{
> >>>sphere{<0,0,0>, 1
> >>>        texture {
> >>>   pigment { color rgbt 1}}
> >>>      interior{media{emission rgb 1
> >>>      density{ spherical
> >>>      color_map{[0 rgb 0][0.03 rgb <0.0004,0,0>][0.6 rgb<8,0,0>][0.98 rgb
> >>>16][1 rgb 30]}
> >>>      }}}
> >>>      hollow
> >>>      scale<0.1, 0.1, 0.1>
> >>>      }
> >>>cylinder{<0,5,0>,<0,0,0>,5}
> >>>       }
> >>>light_source{0 rgb 10 cylinder point_at y*2}
> >>>}
> >>>
> >>>sphere{<.2,.5,-.5>,0.1}
> >>>
> >>>
> >>>Try running this and you'll see the image of the sphere on the laser.
> >>>
> >>>
> >>>
> >>>
> >>Default ior applied to the cylinder
> >>
> >>
> >>
> >>>You'll also see the grey ring where the laser cylinder and the laser
> >>>half-sphere meet(try looking at that location perpendicularly and the grey
> >>>ring disappears).
> >>>
> >>>
> >>>
> >>>
> >>Default texture applied to the substracting cylinder
> >>
> >>
> >>
> >>>You can also see a small white dot on the bottom half-sphere, which is also
> >>>an image of the grey sphere.
> >>>
> >>>
> >>>
> >>Default texture's ior again
> >>
> >>
> >>
> >>>I have a background of stars, and so the ends
> >>>of my laser end up looking speckled.  How can I make all those images and
> >>>grey rings go away?
> >>>
> >>>
> >>>
> >>>
> >>>
> >>1- Remove the ior statement in your default. Thin add an ior to your
> >>cylinder, this is what cause the sphere to apears in your beam.
> >>2- Use merge instead on an union. This will remove the internal surfaces.
> >>3- Use difference{sphere{...}cylinder{...}texture{...}interior{...}}.
> >>That is, apply the texture and interior to the whole
> >>union/difference/intersection/merge. The cylinder get the default
> >>texture and apply it to where it intercect the sphere, giving you that
> >>gray circle.
> >>
> >>Alain
> >>
> >>
> >
> >
> >Thanks, Alain, all the images on the laser are gone now that ior has been
> >deleted. It also helped by making the outer edge fuzzier.  However, I'm
> >still having problems with the grey circle. This time, instead of a grey
> >circle, there's a disk that matches the color of the media (white in the
> >middle, red on the outside), but a little wider than the laser so it
> >doesn't match up (probably b/c removing the ior also seemed to shrink the
> >laser's width a little). Is this what you wanted me to do:
> >
> >merge{
> >
> >
> OK
>
> >cylinder{<0,2*clock1,0>,<0,0,0>, 1                 //the laser, top right
> >   //      texture {
> >   // pigment { color rgbt 1}}
> >       interior{media{emission rgb 1
> >       density{ cylindrical
> >       color_map{[0 rgb 0][0.03 rgb <0.0004,0,0>][0.6 rgb<8,0,0>][0.98 rgb
> >16][1 rgb 30]}
> >       }}}
> >       hollow
> >       scale<0.1, 1, 0.1>
> >       }
> >
> >difference{
> >sphere{<0,0,0>, 1}
> >cylinder{<0,5,0>,<0,0,0>,5}
> >
> >
> Why is it so large? cylinder{<0,1.1,0>,<0,0,0>,1.1} is large enough
> center your sphere and cylinder about <0,0.000001,0> is better, remove
> coincidence surfaces.
>
> >   //      texture {
> >   // pigment { color rgbt 1}}
> >       interior{media{emission rgb 1
> >       density{ spherical
> >       color_map{[0 rgb 0][0.03 rgb <0.0004,0,0>][0.6 rgb<8,0,0>][0.98 rgb
> >16][1 rgb 30]}
> >       }}}
> >       hollow
> >       scale<0.1, 0.1, 0.1>
> >          }
> >
> >
>     texture{pigment{rgbt 1}finish{ambient 0 diffuse 0}}// apply texture
> once to whole merge
>
> >}
> >
> Now, I don't see a discontinuity, as long as I stay with a point of view
> close to perpendiculat near the base, even zooming in, smooth trensition.
>
> Alain

Thanks.  It was the coincident surfaces that were causing my problems.  My
problems are fixed now.

Danny

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