"Danny" <danzaetz> wrote:
> 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

Is there a way I can make the transition smooth even from a point of view
nowhere near perpendicular? It's fine when viewed from the pos. y
direction, but from the neg. y direction it looks like a full sphere (not
half-sphere) in front of a black background, and that the cylinder stops
short and is black when viewed through the base. (I hope you can understand
the picture I'm trying to describe, since I can't attach pictures.)  When I
change it from a merge to a union, it looks fine from the neg. y direction,
but from the pos. y direction the media doesn't transition well. Is there a
way to make it transition well from both directions?

Danny

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