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I'm working on creating a snowglobe and don't know what to do about snow,
does anyone have a tip for creating sparkling particles within the globe?
-Patrick Casteel
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Mary K Casteel wrote:
>
> I'm working on creating a snowglobe and don't know what to do about snow,
> does anyone have a tip for creating sparkling particles within the globe?
> -Patrick Casteel
Snow has a really beautiful crysaline structure when
looked at under a microscope. When floating in the
air on it's merry way to your sidewalks and windshield
on the other hand they look more like irregular shaped
spheres. If I where going to do something like this
I would consider two courses of action.
The first would be to make a group of about 10 - 20
different shaped spheres/blobs and translate them into
a random distribution roughly maintaining a spherical
shape. Declare that as a group. You could then translate
several of the groups within the globe and have a fairly
dense snow field. To really rough up the surface of the
objects take a look at the pov sample file called
quilted.pov. It demonstrates the quilted normal
modifier and would do a pretty good job of creating
enough surface facets that you would need for the light
to bounce from.
The second possibility would be through the use
of Chris Colefax's include files. He has two that
might do the job for you. The first is the object
exploder .inc file which takes a single object or
group of objects and breaks them into a bunch
of smaller pieces.
The second is his particle generator .inc file
whose name is self explanitory.
Chris's include files cane be found at:
http://www.geocities.com/SiliconValley/Lakes/1434/
For a texture I recommend something like --
texture{ pigment {rgb 1}
finish{
ambient .6 // more or less
diffuse .2 // a bit more or less
specular 1
roughness .0001 // a bit more or less
reflection .2 // maybe a bit more/don't over do it
brilliance 1 // or more
// metallic // optional - maybe ?
}
}
The above should be fairly close and it's effectivness
will of course depend on the surface it's applied to
and the angle that the light is striking them.
Ken Tyler
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On Mon, 14 Dec 1998 15:37:04 -0600, "Mary K Casteel"
<KCA### [at] prodigy net> wrote:
>I'm working on creating a snowglobe and don't know what to do about snow,
>does anyone have a tip for creating sparkling particles within the globe?
>-Patrick Casteel
>
Perhaps you could use a number of nested spheres using the starfield
texture (with transparency). By rotating these at different rates you
could get a very nice snow effect. It would be perfect for a snow
globe.
Stefan
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Hmm, could try something like this:
/*untested code, but should be a good starting point*/
//The globe
difference {
sphere {<0, 0, 0>, 5
interior {ior 1.48 caustics .5 fade_distance 9 fade_power 2}
}
sphere {<0, 0, 0>, 4.9
interior {ior 1.33 caustics .5 fade_distance 15 fade_power 2}
}
pigment {color rgbf <.97, .98, .975, .98>}
finish {reflection .05 phong .5 phong_size 70 ambient 0}
}
#declare R1 = seed(1234)
#declare R2 = seed(4321)
#declare R3 = seed(1+2+3+4+4+3+2+1)
#declare make_snow = 0
union {
#while (make_snow < 1000) //how many flakes
sphere {<0, 0, 0>, .01
translate <-5, -5, -5> //move to one corner of the cube
translate <10*rand(R1), 10*rand(R2), 10*rand(R3)> //then spread around
}
#declare make_snow = make_snow + 1
#end
/*This should be the shape of the globe*/
bounded_by { sphere {<0, 0, 0>, 4.899} }
pigment {color White}
finish {ambient .5}
}
That should work pretty good unless you want to animate it.
-Mike
Mary K Casteel wrote:
>
> I'm working on creating a snowglobe and don't know what to do about snow,
> does anyone have a tip for creating sparkling particles within the globe?
> -Patrick Casteel
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The easiest (gulp, not really) way to do this is make a particle system.
For the particles use triangles, although they sound rather primitive, they
do produce a good looking snow because of the way the light reacts with them
as they tumble. It might be hard to simulate this with POV-Ray. I oce
tried to make a particle system with POV-Ray but ended in failure. The only
really good snow I was able to make was with MAX's particle dynamics. Once
again, I used triangles (although facing triangles are a good way to start,
by facing I mean camera normalised). This is the best way to go about
animating it. If you're planning on doing any kind of animation it's best
of have a particle system (perhaps POV-Ray's macros would help, I've never
used macros so I wouldn't know, I presume it's like MAXScript, in which case
it would help tremedously!). There are a few particle simulators out there
but I'm not sure if you could convert the particles to POV-Ray.
--
Lance.
---
For the latest MAX plug-ins, images and much more, go to:
The Zone - http://come.to/the.zone
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It would be my inclination to use triangles (or some polygon) for the snow.
In the real world falling snow can assume a variety of characteristics, but in
a snow globe the stuff seems to be composed of little white chips which are
generally flat. (I may be wrong here since I have not taken one of these things
in hand for some time.) Further, as has been mentioned, randomly oriented flat
surfaces (e.g. triangles) would help achieve the twinkling effect.
If the final rendering is to be a still image, filling a spherical space with
whatever objects randomly distributed should present no problem . However, if
it is to be an animation, I would agree with previous posts that the problem
becomes a little more complex - though being constrained to a sphere volume as
opposed to a box may be a good thing.
Abe
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Ho Mike.
I jump in here with a THANKYOU.
I posted a line about this pice called 3D match a while up...
Hadn't found the bounded_by statement... Or was to dumb to use it....
Thanx again...
But, the question remains... What are the formula to test if a pont is inside a sphere
(useful in a few othjer progs I'm doing... ??
Well, thankya again...
AS for the snowflakes, try a scaled sphere.... scale <0.1,1,1> or so... Then a
rotation...
//Spider
Mike wrote:
>
> Hmm, could try something like this:
>
> /*untested code, but should be a good starting point*/
>
> //The globe
>
> difference {
>
> sphere {<0, 0, 0>, 5
> interior {ior 1.48 caustics .5 fade_distance 9 fade_power 2}
> }
>
> sphere {<0, 0, 0>, 4.9
> interior {ior 1.33 caustics .5 fade_distance 15 fade_power 2}
> }
>
> pigment {color rgbf <.97, .98, .975, .98>}
> finish {reflection .05 phong .5 phong_size 70 ambient 0}
>
> }
>
> #declare R1 = seed(1234)
> #declare R2 = seed(4321)
> #declare R3 = seed(1+2+3+4+4+3+2+1)
>
> #declare make_snow = 0
>
> union {
>
> #while (make_snow < 1000) //how many flakes
>
> sphere {<0, 0, 0>, .01
> translate <-5, -5, -5> //move to one corner of the cube
> translate <10*rand(R1), 10*rand(R2), 10*rand(R3)> //then spread around
> }
>
> #declare make_snow = make_snow + 1
> #end
>
> /*This should be the shape of the globe*/
> bounded_by { sphere {<0, 0, 0>, 4.899} }
>
> pigment {color White}
> finish {ambient .5}
> }
>
> That should work pretty good unless you want to animate it.
>
> -Mike
>
> Mary K Casteel wrote:
> >
> > I'm working on creating a snowglobe and don't know what to do about snow,
> > does anyone have a tip for creating sparkling particles within the globe?
> > -Patrick Casteel
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Mary K Casteel wrote:
>
> I'm working on creating a snowglobe and don't know what to do about snow,
> does anyone have a tip for creating sparkling particles within the globe?
> -Patrick Casteel
I'll add my non-realistic two cents to the other suggestions.
I made a small animation with snow some time ago and found this made a great
difference. For the flakes I used simple white spheres, but with a high ambient
value. Snow IS white, after all...
Regards,
Remco
http://www.xs4all.nl/~remcodek/
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Spider wrote:
>
> Ho Mike.
> I jump in here with a THANKYOU.
> I posted a line about this pice called 3D match a while up...
> Hadn't found the bounded_by statement... Or was to dumb to use it....
>
> Thanx again...
> But, the question remains... What are the formula to test if a pont is inside a
sphere
> (useful in a few othjer progs I'm doing... ??
>
> Well, thankya again...
> AS for the snowflakes, try a scaled sphere.... scale <0.1,1,1> or so... Then a
rotation...
>
> //Spider
>
Couldn't be simpler in POV,
#if( vlength( Point - SphereCentre ) < SphereRadius )
...
#end
if it's not in POV
X = Point.x - SphereCentre.x
Y = Point.y - SphereCentre.y
Z = Point.z - SphereCentre.y
D = X*X + Y*Y + Z*Z
if( D < SphereRadius * SphereRadius )
Cheers, PoD.
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Once again...
There was a new reply in teh 3d math thread, using a good algorithm..
It was posted by Abe (Thanx)
Try it out, it should(may) be what you want...
//Spider
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