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See below, I'm trying to illuminate the scene with a "fire".
The cylinder object gives me a nice looking fire, (complicated)
and the chalice object is fine, but the light sources which should be up in the
fire object, don't seem to get OUT.
What did I miss?
#declare Fire = object { union { cylinder { <0,0.01,0>, <0,3,0>, 1.0 hollow
material { Flame }
translate <-0,0.5,0>
no_shadow
}
object { Chalice rotate <0, 0, 0>
photons { target 1.0
refraction off
reflection on
}
}
light_source { 0*y
color rgb 1.50
area_light
<0.0, 1.0, 0.0> <0.0, 2.0, 0.0>
8, 1
adaptive 1
orient
}
}
}
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"Dave VanHorn" <mic### [at] gmail com> wrote in message
news:web.49063d6478db427ea08ed15e0@news.povray.org...
>
> The cylinder object gives me a nice looking fire, (complicated)
> and the chalice object is fine, but the light sources which should be up
> in the
> fire object, don't seem to get OUT.
Hmmmm. You don't show what your Flame is made of, such as filtered pigment
or media, but I'm not sure why you aren't seeing any light from the fire. I
ran a render of what you are trying using my own fire material and other
than no_shadow preventing shadowing from the fire cylinder I can see the
light source.
Your area_light isn't what I've ever used or recall seeing used, having no
perpendicular axis to make the grid of lights. And yet that doesn't seem to
be the actual problem you are getting there, if mine rendered the same here.
Just to be sure, I changed it to be <1,0,0>,<0,2,0>,5,10 so I could see
everything else wasn't wrong in some way.
Something to keep in mind about area_light is how it is still like a point
source when it comes to location and other things unrelated to the shadowing
it causes. So other than shadows it is like a regular point of light.
Also not knowing your Chalice object means it is possible a surface is
obscuring the light. There might be a clue by how your fire object has a
bottom slightly above the light_source, perhaps meaning your Chalice has a
surface at the same place? So remember area_light remains a point-like
source based on its location and not the grid being created.
Maybe that will help.
Bob H.
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"Bob Hughes" <omniverse charter net> wrote:
> "Dave VanHorn" <mic### [at] gmailcom> wrote in message
> news:web.49063d6478db427ea08ed15e0@news.povray.org...
> >
> > The cylinder object gives me a nice looking fire, (complicated)
> > and the chalice object is fine, but the light sources which should be up
> > in the
> > fire object, don't seem to get OUT.
>
>
> Hmmmm. You don't show what your Flame is made of, such as filtered pigment
> or media, but I'm not sure why you aren't seeing any light from the fire. I
> ran a render of what you are trying using my own fire material and other
> than no_shadow preventing shadowing from the fire cylinder I can see the
> light source.
It's a complicated thing, but it's not causing the lights not to get out.
> Your area_light isn't what I've ever used or recall seeing used, having no
> perpendicular axis to make the grid of lights. And yet that doesn't seem to
> be the actual problem you are getting there, if mine rendered the same here.
The docs say you can make it a linear light by doing X1 in one axis.
> Just to be sure, I changed it to be <1,0,0>,<0,2,0>,5,10 so I could see
> everything else wasn't wrong in some way.
> Something to keep in mind about area_light is how it is still like a point
> source when it comes to location and other things unrelated to the shadowing
> it causes. So other than shadows it is like a regular point of light.
Right.. I'm seeing light from it now, but I'm not seeing the softened shadows,
which I should be..
> Also not knowing your Chalice object means it is possible a surface is
> obscuring the light. There might be a clue by how your fire object has a
> bottom slightly above the light_source, perhaps meaning your Chalice has a
> surface at the same place? So remember area_light remains a point-like
> source based on its location and not the grid being created.
It should be, but not completely. That's what I intend.
I thought I'd outsmart it and use a "looks like" to find out where the lights
are, but that just gives one sphere no matter how many lights I specify.
This version is sort of working..
#declare Fire = object { union { cylinder { <0,0.01,0>, <0,3,0>, 1.0 hollow
material { Flame }
translate <-0,0.5,0>
no_shadow
}
object { Chalice rotate <0, 0, 0>
photons { target 1.0
refraction off
reflection on
}
}
light_source { <0,0,0>
// light's position
color rgb 0.250
// light's color
area_light
<0.0, 0.0, 0.0> <0.0, 1.0, 0.0>
// lights spread out across this distance (x * z)
1, 8
// total number of lights in grid (4x*4z = 16 lights)
adaptive 1
// 0,1,2,3...
fade_distance 2
//
fade_power 2
//
translate <0, 2.0, 0>
//
// Good for locating the lights
looks_like {sphere { <0, 0, 0>,
0.25 }}
}
}
}
#declare Chalice = object { union { cone { 1*y, 0.75,
0, 0.0
open
//material { M_Glass }
texture { T_Brass_3E
normal { bumps 0.1 scale
0.05 }
}
}
cone { 1*y, 0.0,
0, 0.75
open
}
}
}
#declare Flame = material { texture { pigment {rgbt 1.00} } // Just plain clear
interior {
//Explosive interior
media { // POV-Ray supports three types of media:
emissive,
// absorbing, and scattering. "emission" is
self-illuminated
// media. it will not cast light on other
objects, but it
// has the appearance of glowing.
"absorption" blocks light
// instead of emits light. absorbing media
casts shadows on
// other objects. "scattering" media is lit
by other
// light sources, and can scatter light. it
is substantially
// slower to render than the other two
types, however, it
// can be used with photons to create
effects like
// visible sunbeams
emission 5.0
absorption 5.5
// LAYER 1
//
// for our first layer, we'll blend the edge
of the sphere
// to transparent. this will make edges less
obvious and help
// hide the fact that the media is contained
inside a sphere.
// we want it to look free-floating, so it's
important to
// disguise the edges
density { spherical
density_map { [0.0 rgb <0.0, 0.0,
0.0>]
[1.0 rgb <1.0, 1.0,
1.0>]
}
}
// LAYER 2
//
// explosions usually have bright centers.
for our second layer,
// we'll give the explosion a "hot" core by
multiplying past
// the 1.0 range in the center... POV-Ray
doesn't support HDRI
// (the MegaPOV build does) but this trick
works nonetheless
density { spherical
density_map { [0.7 rgb <1.0, 1.0,
1.0>]
[1.0 rgb <8.0, 8.0,
8.0>]
}
}
// LAYER 3
//
// now that we've blocked out the general
shape of our media,
// for our third layer we want to get it
looking more cloud-like
// and less like a ball. we'll do that by
adding some soft, low
// frequency turbulence
density { spherical
density_map { [0.00 rgb <0.0, 0.0,
0.0>]
[0.20 rgb <0.5, 0.0,
0.0>]
[0.40 rgb <0.8, 0.4,
0.0>]
[0.85 rgb <0.2, 0.2,
0.6>]
[0.95 rgb <0.1, 0.1,
1.0>]
}
// here's where the magic
happens... a low turbulence setting
// causes our media to take on a
soft, cloud-like shape
warp { turbulence 0.6
lambda 1.5
// low omega values create
soft, blurry results;
// higher values are crisp
and wrinkly
omega 0.50
}
// this warp causes the explosion
to look like the particulate
// is ejecting from the center by
pulling in all of the color
// toward the center... I haven't
tried it, but I bet you
// could do some nifty animations
by adding a clock term to
// one of these values
warp { black_hole <0.0, 0.0, 0.0>,
2.0
strength .95
falloff 2.5
}
}
//
// LAYER 4
//
// explosions have lots of detail, with many
fine swirls and
// eddies. we can simulate this by using a
high-frequency
// turbulence value. again, we'll multiply
past 1.0 to keep
// the explosion "hot"
density { spherical density_map { [0.0 rgb
<0.0, 0.0, 0.0>]
[0.1 rgb
<1.0, 0.0, 0.0> * .75]
[0.2 rgb
<1.0, 0.5, 0.0> * .75]
[0.8 rgb
<1.0, 1.0, 2.0> * 2.5]
}
warp { turbulence 1.5
lambda 2.5
omega 0.55
octaves 7
}
scale .75
warp { black_hole <0.0, 0.0, 0.0>,
2.0
strength .8
falloff 2.0
}
}
// if you find that you have glitches or black
spots in
// your media, try turning up the number of
samples.
// more samples will cause it to render
slower, so don't
// turn it up more than you need to
samples 20
scale <0.500, 2.00, 0.500>
translate <0.0, 1.0, 0.0>
}
}
}
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"Dave VanHorn" <mic### [at] gmailcom> wrote in message
news:web.4907254237e3ca30a08ed15e0@news.povray.org...
> "Bob Hughes" <omniverse charter net> wrote:
>
>> Your area_light isn't what I've ever used or recall seeing used, having
>> no
>> perpendicular axis to make the grid of lights. And yet that doesn't seem
>> to
>> be the actual problem you are getting there, if mine rendered the same
>> here.
>
> The docs say you can make it a linear light by doing X1 in one axis.
You're right. My mistake. First sentence from the docs says so, and now I
realize I have done that before. I was trying to recall the docs and was
only thinking of the grid made from two axes. Awful memory. ;^)
>
>> Also not knowing your Chalice object means it is possible a surface is
>> obscuring the light. There might be a clue by how your fire object has a
>> bottom slightly above the light_source, perhaps meaning your Chalice has
>> a
>> surface at the same place? So remember area_light remains a point-like
>> source based on its location and not the grid being created.
>
> It should be, but not completely. That's what I intend.
> I thought I'd outsmart it and use a "looks like" to find out where the
> lights
> are, but that just gives one sphere no matter how many lights I specify.
Okay. I neglected to mention keyword 'jitter' before since I thought you
must know of it and were trying for banded shadows from the flames. I'm
guessing now you might have been wanting to use that afterall to smooth the
shadows.
I rendered your new example (without the line wrap, heh-heh!) and I see you
lowered the light brightness drastically. It seems to do as expected. I
changed the light color to rgb <0.75,0.5,0.5> to give it color something
like the flame itself and the brightness makes for better shadowing so I
could see what was going on. I also put the whole thing into a 10 unit
radius room (white sphere) with a floor (white plane at y=0). That
fade_distance and fade_power both being 2 really dims quickly.
Getting back to the idea of a linear light... if I were you I'd put some
width on the flame light. That could be part of the trouble with the
shadows. When I used:
area_light <0.5,0,0>,<0,1.5,0>,5,15 jitter
it really helps smear out shadows of objects placed around the flame. In
fact, if you were to animate it I would try varying the area grid a little
to move the shadows by putting small random numbers added/subtracted to the
vectors.
Something else I'm not keeping familiar with these days is 'orient' which
you originally had used in area_light. I found it to make shadows grainy so
I upped the grid numbers (5,15) to make that better.
Hope you get this looking how you need it.
Bob H.
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Dave VanHorn nous illumina en ce 2008-10-28 10:44 -->
> "Bob Hughes" <omniverse charter net> wrote:
>> "Dave VanHorn" <mic### [at] gmailcom> wrote in message
>> news:web.49063d6478db427ea08ed15e0@news.povray.org...
>>> The cylinder object gives me a nice looking fire, (complicated)
>>> and the chalice object is fine, but the light sources which should be up
>>> in the
>>> fire object, don't seem to get OUT.
>>
>> Hmmmm. You don't show what your Flame is made of, such as filtered pigment
>> or media, but I'm not sure why you aren't seeing any light from the fire. I
>> ran a render of what you are trying using my own fire material and other
>> than no_shadow preventing shadowing from the fire cylinder I can see the
>> light source.
>
> It's a complicated thing, but it's not causing the lights not to get out.
>
>
>> Your area_light isn't what I've ever used or recall seeing used, having no
>> perpendicular axis to make the grid of lights. And yet that doesn't seem to
>> be the actual problem you are getting there, if mine rendered the same here.
>
> The docs say you can make it a linear light by doing X1 in one axis.
If you make a linear area_light, then you can't use orient. Your's have 2
parallel axis.
The first two value are the extent of the area_light, the next two are the
number of elements along each axis.
Apparently, you want it to be vertical, long and thin. So:
<0.1,0,0><0,2,0> for the dimentions and
3,33 for the elements
then add "jitter" to soften the shadow even more.
With adaptive, 9, 17, 33, 65,... are effecient values. 8 is not an effecient value.
>
>> Just to be sure, I changed it to be <1,0,0>,<0,2,0>,5,10 so I could see
>> everything else wasn't wrong in some way.
>> Something to keep in mind about area_light is how it is still like a point
>> source when it comes to location and other things unrelated to the shadowing
>> it causes. So other than shadows it is like a regular point of light.
>
> Right.. I'm seeing light from it now, but I'm not seeing the softened shadows,
> which I should be..
>
>> Also not knowing your Chalice object means it is possible a surface is
>> obscuring the light. There might be a clue by how your fire object has a
>> bottom slightly above the light_source, perhaps meaning your Chalice has a
>> surface at the same place? So remember area_light remains a point-like
>> source based on its location and not the grid being created.
>
> It should be, but not completely. That's what I intend.
> I thought I'd outsmart it and use a "looks like" to find out where the lights
> are, but that just gives one sphere no matter how many lights I specify.
>
--
Alain
-------------------------------------------------
I knew a girl so ugly, they use her in prisons to cure sex Offenders.
Rodney Dangerfield
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I got it working right, it was a problem where the light sources weren't where I
thought they'd be.
I thought I could get around it by using "looks_like", but that just gave me a
single sphere in the center of the array.
Still, it's working now, thanks for the tips guys!
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