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I'm trying to create the disturbance to the atmosphere as a meteor
passes through it. Kind of like ripples in the air, that sort of thing. Is
there any way in Pov or MegPov to do this?
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kane wrote:
>
> I'm trying to create the disturbance to the atmosphere as a meteor
> passes through it. Kind of like ripples in the air, that sort of thing. Is
> there any way in Pov or MegPov to do this?
You probably mean the effect caused by varying IOR of the air. This is not
possible in POV, Mega or regular.
You can simulate it with a (large) number of transparent objects with different
IORs, representing the varying density layers of air. But I don't really
recommend it unless you have a Cray and a LONG vacation ahead of you.
--
Margus Ramst
Personal e-mail: mar### [at] peak eduee
TAG (Team Assistance Group) e-mail: mar### [at] tagpovrayorg
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kane wrote:
> I'm trying to create the disturbance to the atmosphere as a meteor
> passes through it. Kind of like ripples in the air, that sort of thing. Is
> there any way in Pov or MegPov to do this?
Possibly an isosurface with transparency and ior could do this, but it
wouldn't be very easy.
G.
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Wouldn't the isosurface give sharp edges?
Gilles Tran wrote:
> kane wrote:
>
> > I'm trying to create the disturbance to the atmosphere as a meteor
> > passes through it. Kind of like ripples in the air, that sort of thing. Is
> > there any way in Pov or MegPov to do this?
>
> Possibly an isosurface with transparency and ior could do this, but it
> wouldn't be very easy.
> G.
--
Samuel Benge
E-Mail: STB### [at] aolcom
Visit my isosurface tutorial at http://members.aol.com/stbenge
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Wasn't it SamuelT who wrote:
>Gilles Tran wrote:
>
>> kane wrote:
>>
>> > I'm trying to create the disturbance to the atmosphere as a meteor
>> > passes through it. Kind of like ripples in the air, that sort of thing. Is
>> > there any way in Pov or MegPov to do this?
>>
>> Possibly an isosurface with transparency and ior could do this, but it
>> wouldn't be very easy.
>> G.
>
>Wouldn't the isosurface give sharp edges?
The shockwaves produced by a meteor travelling at hypersonic velocity
will actually have sharp edges, so that shouldn't be a problem.
A bigger problem is that very few people (if any) have ever observed
atmospheric disturbances caused by meteors, so it's going to be hard to
check whether the rendering is remotely realistic. None of the meteors
that I've seen have caused any observable atmospheric disturbances.
--
Mike Williams
Gentleman of Leisure
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I've given this some thought and I suggest using a normal in the camera
statement, with a pattern like ripples being oriented in relation to
where the meteor path line of sight is at. Might take a normal map of
some ingenious design to accomplish.
Well, maybe not ingenious, however here's something I tried just now.
Bob
/* example of creating shockwave in air (no vapor) */
global_settings {
number_of_waves 0
}
#declare Amplitude=0.333; // amount of shockwave effect
#declare Frequency=6; // number of peaks and troughs
#declare xSize=0.5; // lengthwise curvature (or size)
#declare zSize=0.25; // crosswise curvature (more curve when less than
xSize)
#declare xPos=-2; // move ripples off-center
#declare Width=0.45; // pie-slice region of air displacement (<1.0 but
>0.5)
#declare EntryAngle=-30; // angle of attack
#declare Placement=<0.25,-0.075,0>; // offset from center, small values
of x and y (no z)
#declare N0=normal {ripples 0} // dummy normal
#declare N1=normal {ripples Amplitude frequency Frequency scale
<xSize,1,zSize> translate xPos*x}
camera {
location 0
look_at 1*z
normal {radial normal_map {
[Width N0][0.5 N1][1-Width N0]
} ramp_wave rotate 90*x
rotate EntryAngle*z translate Placement}
}
light_source {<10,10,-10>, 1}
sphere {0,1
pigment {gradient y color_map {
[0 color rgb <.9,.6,.3>]
[.1 color rgb <.6,.3,.6>]
[.3 color rgb <.4,.6,.8>]
[.6 color rgb <.2,.4,.6>]
}}
finish {ambient .5}
scale 1000
}
// meteor (test object: note that this really messes up if shockwave is
intense)
cone {-x,1,0,.1 scale <100,10,10>
pigment {granite color_map {
[0 color rgb <.9,.8,.7>]
[1 color rgb <.7,.6,.4>]
}}
finish {ambient .75}
rotate EntryAngle*z translate <25,-5,100> // placing this is only a
guess
no_shadow
}
"kane" <ann### [at] mindspringcom> wrote in message
news:392b3ffd@news.povray.org...
| I'm trying to create the disturbance to the atmosphere as a meteor
| passes through it. Kind of like ripples in the air, that sort of
thing. Is
| there any way in Pov or MegPov to do this?
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"Mike Williams" <mik### [at] nospamplease> wrote in message
news:JOt### [at] econymdemoncouk...
> A bigger problem is that very few people (if any) have ever observed
> atmospheric disturbances caused by meteors, so it's going to be hard to
> check whether the rendering is remotely realistic. None of the meteors
> that I've seen have caused any observable atmospheric disturbances.
It seems to me that you would have to be pretty darn close to the meteor to
actually see the shockwave, and if you were that close, your ability to see
it would still depend on several other factors: 1) Light; 2) Atmospheric
conditions; 3) The limits of human field-of-vision in tracking, at close
range, an object moving at supersonic speed; 4) The natural tendency to
duck.
I do have an mpeg of a condensation ring forming around a jet as it attains
the speed of sound. It is, of necessity, short.
--
simon.A
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SamuelT wrote:
> Wouldn't the isosurface give sharp edges?
>
I was thinking of an isosurface with very thin edges (with no ripples) and a thick
center (with the ripples). No, I don't have the equation...
G.
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Hmm, it could be done, but it would have to face the camera, probably. Hmm.....
Gilles Tran wrote:
> SamuelT wrote:
>
> > Wouldn't the isosurface give sharp edges?
> >
>
> I was thinking of an isosurface with very thin edges (with no ripples) and a thick
> center (with the ripples). No, I don't have the equation...
> G.
--
Samuel Benge
E-Mail: STB### [at] aolcom
Visit my isosurface tutorial at http://members.aol.com/stbenge
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kane wrote:
> I'm trying to create the disturbance to the atmosphere as a meteor
> passes through it. Kind of like ripples in the air, that sort of thing. Is
> there any way in Pov or MegPov to do this?
My ParticlePatch, which I just released (see p.u.p/p.p) may be able to help
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