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> I've used POV for a long time, but I find lighting to be one of my biggest
> challenges in scene development. I thought it might be interesting to get some
> examples from the community on creative ways to light a scene:
>
> Below is a primitive scene (no pun intended) with only a basic light source.
> With the restriction that you aren't allowed to change the camera or the objects
> (including their mundane textures), what creative lighting solutions can you
> come up with to make this image more interesting?
>
>
>
The most important thing is the light placement, as depending on it the
shadows play will be interesting or boring. It's a difficult subject,
because it depends on the composition, but I usually play with rand() to
find interesting placements... after trying some seeds, you may get an idea
of which placements make for interesting shots (for this scene, and in
general too):
#version 3.6;
#include "colors.inc"
global_settings {
assumed_gamma 1.0
max_trace_level 10
radiosity{count 160 error_bound 0.5 nearest_count 10}
}
#default{texture{finish{ambient 0 diffuse 1}}}
#declare r_l=seed(117);
light_source { <-10-10*rand(r_l), 10*rand(r_l), -10-10*rand(r_l)>
color rgb White*150
area_light 1*x,1*z,4,4 jitter adaptive 1 orient circular
fade_distance 1
fade_power 2
rotate 360*rand(r_l)*y
}
light_source { <-10-10*rand(r_l), 10*rand(r_l), -10-10*rand(r_l)>
color rgb Gold*100
area_light 1*x,1*z,4,4 jitter adaptive 1 orient circular
fade_distance 1
fade_power 2
rotate 360*rand(r_l)*y
}
// ----------------------------------------
// Basically, everything below here should
// remain the same
// ----------------------------------------
#include "glass.inc"
camera {
location <0, 5, -5>
look_at <0, 0, 0>
}
plane {
y, -1
texture {
pigment {
gradient x
color_map {
[0.0 rgb <0.6, 0.4, 0.4>]
[0.5 rgb <0.2, 0.6, 0.8>]
[1.0 rgb <0.6, 0.4, 0.4>]
}
scale 4
rotate -45*y
}
normal {
granite
0.6
scale 1.75
}
}
}
box {
-1, 1
scale <1,0.999,1>
texture{
pigment {
gradient y
color_map {
[0.0 rgb <0.9, 0.1, 0>/8]
[1.0 rgb <0.9, 0.1, 0>]
}
scale 2
translate -y
}
finish {
diffuse 0.6
brilliance 1.0
phong 0.5
phong_size 40
specular 0.5
roughness 0.05
metallic 1
reflection {
0.5
1.0
fresnel on
falloff 1.0
exponent 1.0
metallic 0.9
}
conserve_energy
}
normal {
granite 0.15
scale 2
}
}
rotate 25*y
translate <-3.25,0,2>
}
sphere {
0, 1
texture {
pigment {
bozo
color_map {
[0.0 rgb <1,1,0>]
[1.0 rgb <0,0,2>]
}
scale 0.2
}
finish {
brilliance 0.4
phong 0.25
phong_size 70
specular 0.65
roughness 0.005
}
}
translate <0,0,3>
}
torus {
1.0,
0.25
texture {
pigment {
gradient x
color_map {
[0.0 rgb <1,0,1>/1]
[0.3 rgb <1,0,1>/4]
[0.6 rgb <1,0,1>/2]
[1.0 rgb <1,0,1>/1]
}
scale 0.25
warp {
turbulence 0.25*x
}
}
finish {
diffuse 0.8
brilliance 1.0
phong 0.5
phong_size 25
specular 0.15
conserve_energy
}
}
translate <1.75,-0.75,-1.75>
}
cone {
-y,2,
2*y,0
material {
texture {
pigment {
color Col_Glass_Orange
}
finish {F_Glass3}
}
interior {I_Glass}
}
translate <4,0,3>
}
cylinder {
<-2,-0.5,-2>, <0,-0.5,0>, 0.5
texture {
pigment {
dents
color_map {
[0.0 rgb <1,1,0>/2]
[0.5 rgb <1,1,0>]
[1.0 rgb <1,1,0>/2]
}
scale 1/4
}
normal {
crackle 1.5
scale 1/4
}
}
translate <-1,0,-1>/2
}
--
Jaime Vives Piqueres
http://www.ignorancia.org
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Jaime Vives Piqueres <jai### [at] ignorancia org> wrote:
> The most important thing is the light placement, as depending on it the
> shadows play will be interesting or boring. It's a difficult subject,
> because it depends on the composition, but I usually play with rand() to
> find interesting placements... after trying some seeds, you may get an idea
> of which placements make for interesting shots (for this scene, and in
> general too):
That's very interesting. I've found it surprisingly useful to use the rand
function to try different colors, but never light placement. That's a great
idea!
Regards,
Dave Blandston
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> I've used POV for a long time, but I find lighting to be one of my biggest
> challenges in scene development. I thought it might be interesting to get some
> examples from the community on creative ways to light a scene:
>
> Below is a primitive scene (no pun intended) with only a basic light source.
> With the restriction that you aren't allowed to change the camera or the objects
> (including their mundane textures), what creative lighting solutions can you
> come up with to make this image more interesting?
>
Can we add a photons block to some objects, like the glass cone and the
reflective box?
Using area_light can often help. Use adaptive starting with adaptive 0
to speed up the rendering.
Use relatively high sampling: 9x9, 17x17, 33x33, 65x65,...
Using several coloured lights can be very interesting.
There are things in the textures that can andicap you.
Take this finish from the sphere:
finish {
brilliance 0.4
phong 0.25
phong_size 70
specular 0.65
roughness 0.005
}
You have a strong, relatively tight highlight, but, at the same time a
prety low briliance.
Increasing brilliance to some value between 1 and 2 gives more a
beleivable result.
The box have fresnel in it's reflection, but don't have an interior, and
thus no ior. fresnel won't work. Also, conserve_energy is similarly
useless as there is no transparency.
Same comment about conserve_energy for your torus.
Alain
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"Dave Blandston" <nomail@nomail> wrote:
> That's very interesting. I've found it surprisingly useful to use the rand
> function to try different colors, but never light placement. That's a great
> idea!
I agree! I've never thought to do that, either. Thanks, Jamie!
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Alain <aze### [at] qwertyorg> wrote:
> Can we add a photons block to some objects, like the glass cone and the
> reflective box?
Sure, I think that's still in the spirit of things.
> You have a strong, relatively tight highlight, but, at the same time a
> prety low briliance.
> Increasing brilliance to some value between 1 and 2 gives more a
> beleivable result.
Good points, thanks.
> The box have fresnel in it's reflection, but don't have an interior, and
> thus no ior. fresnel won't work. Also, conserve_energy is similarly
> useless as there is no transparency.
> Same comment about conserve_energy for your torus.
Yeah, another good point -- I was cutting and pasting from the default textures
and not really paying attention. :) Thanks for the tips here, too.
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How Camp wrote:
> what creative lighting solutions can you come up
> with to make this image more interesting?
I saw this in the morning before embarking on a lengthy
train ride so I've been playing with this on my netbook.
I missed the rest of the discussion but also came to the
conclusion that adding photon blocks would be ok ;)
I wasn't quite sure whether not changing the objects meant
you couldn't add any object to the scene. Using radiosity is
a bit sad if the environment is completely black, so I added
a blueish dome with ambient > 0 around the scene, which I
suppose is still in the spirit of lighting the thing.
Due to the 3.6 directive I wasn't sure about 3.7 features
either (mainly HDRI and area_illumination) so I left them out
for now. I didn't have any HDRI images available anyway ;)
I also skipped focal blur as it's strictly speaking not
a lighting but a camera effect.
Post a reply to this message
Attachments:
Download 'challenge-strict.jpg' (38 KB)
Preview of image 'challenge-strict.jpg'
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/*
Hi How Camp
The problem of lightning has its origin in the techniques of CGI-Lightning!
Means: Years ago there was no way to simulate light that correct, as it is in
nature. And it's still not possible - but you can come very close to it with in
these days.
Studio-light often tries to simulate daylight by using special techniques
insight of the studio.
The result was to have _very_ special techniques in CGI-lightning: Simulating
light with a program, that can not offer you _real_ working light-simulation
makes it twice-complicate just to get a good looking studio-situation. Using a
studio-situation to make a good looking light-situation then is the next step to
make.
First is to understand the classic limitations and then making the decision,
using the classic way, ore the classic way with further techniques, or using
progressive techniques.
First way means: Hard setup for the artists, but fast render-time.
Second way means: _Much_ easier setup, slower render-time (radiosity)
Third way means: Easy setup as well, very slow rendering, but very accurate
lighting-simulation. (Path-tracing, by using MC-Pov)
Best start is to take a look of the problems in the classic way of light
simulation (the classic way of ray-tracing).
Lets take a look of whats NOT possible:
- Light comes _ONLY_ from out of the light-source! In real environment it comes
from _everywhere_ that is visible to your eye, or to the camera, because the
light-rays that makes an object visible could light up other objects as well if
not going into your eye!
- When having _NO_ light in the shadows (because these areas are somehow covert
from the light-sources) that means: Totally blackness! to avoid this, these
areas can be lighten up, using the "ambient" keyword. What happens then is a so
called "self-illumination" within that areas. Actually there NOT illuminating
the scene, there JUST illuminating "to the camera".
These "tool" is actually the MOST artificial looking problem in lighning!
Your scene contains objects, heaving the "ambient" setting set to "0.1" try out,
to set it to "0" and using other light-sources (very small values in power,
using light fading and make it "shadowless". With this technique, you can try to
setup reflecting light, coming from important, and big surfaces, illuminating
other objects.
This technique means very much work, but a better result as when setting the
ambient higher then zero.
In a photo-studio, reflectors are often used.
When no light is simulated, coming from objects, you have to use the same
technique of shadowless and fading light-sources to illuminate special areas.
A basic rule is: Only the main light has a shadow. More then one main shadow is
something, a professional photographer would never except. (For a normal setup)
You see this is a very hard job to make.
When using ambient, higher then zero, try out to bring negative lights into
special eras, like insight mouth and nose. As well, use no-shadow, and fading
here!
A much easier thing might be to set all your ambients to zero, than try out
different radiosity settings from the "rad_def.inc" file. For this test, use
only one light-source in the beginning.
This is, what is being tried in every photo-studio to simulate, when using lambs
in a setup: The sun! This is your main-light. Other lights coming from other
object (we _don't_ have two suns, or more up in the sky ;)
When the result is good, try to make the environment a little cloudy, by using
an area-light instead of a point- or spotlight. In most cases, this looks more
friendly.
You can use objects as light-sources, when using radiosity, or when using
MC-Pov. THIS time, when using the ambient keyword, and using radiosity, or
MC-Pov the object will REALY self-illuminate AND lightning other objects as well
as a normal light-source.
This is good for soft shadows.
Another big problem are the surfaces, because the highlights on an object is
separated from the shape of the light, and the reflection of the finish. Means:
It is possible, making a very blurry highlight, but still a clean, reflective
surface. In normal cases, this is not possible. A soft highlight means a rugh
surface and that means a blurry reflection!
In this example, I try to bring the most popular tricks.
Best regards,
Holger :)
*/
//#######################################################################################
#declare Scenetype=0; // 0=PovRay no Radiosyty (area_light)
// 1=PovRay with Radiosity (no blurry reflection,
because of allredy existing normals)
// 2=MC-POV (Blurry reflection)
//########################## LightSoftness effects the size of the ligtsource
####################
#declare LightSoftness=6;
//########################## The reflector makes the environment more friendly
#######
#declare Reflector=off;
//#######################################################################################
// Only works in MC-Pov mode. These are settings for all objects eccept the
cone
#declare LightSoftness_onSurfaces=25;//smaller = more blurry
#declare LightIntensity_onSurfaces=.25;
// For the ground
#declare LightSoftness_onSurfaces_on_floor=10;
#declare LightIntensity_onSurfaces_on_floor=.1;
//#######################################################################################
/*
When using Scenetype=1 no Highlights will be shown, because of no
blurry reflection in the scene.
Blurry reflection with PovRay is only availiable, when
no other normals are used (or I don't know how to...)
Only the cone has a hilight (normal reflection..)
(Lightsources will not be shown to the camera, or reflections, only
objects does)
*/
//########################## have fun
###########################################
#include "colors.inc"
#include "glass.inc"
#include "rad_def.inc"
#if (Scenetype=2) #version unofficial megapov 1.21 #else #version 3.6;#end
global_settings {
assumed_gamma 1.0
max_trace_level 10
#if (Scenetype=1) radiosity {Rad_Settings(Radiosity_IndoorLQ,on,off)}#end//HQ
was to slow for my taste
#if (Scenetype=2)
max_trace_level 8
montecarlo
{
mc_rand_seed
mc_max_diffuse_bounce 3
mc_pixel_refresh_ratio 1
}
#end
}
#default{pigment{color rgb 1}finish{ambient 0 diffuse 1
#if (Scenetype=2)
montecarlo{mc_diffuse{1 1 1}}
#end
}}
#if (Scenetype=0)
light_source {
0*x
color rgb 30
area_light
<LightSoftness,0,0><0,0,LightSoftness>
4,4
adaptive 0
jitter
circular
orient
rotate <-20,15,0>
translate <5, 10, -10>
fade_distance 2
fade_power 2.2
}
#end
#if (Scenetype=0) #else
box{<LightSoftness,-.1,-.1><.1,.1,LightSoftness>
#if (Scenetype=2)
montecarlo{mc_portal{1 1 1 1}}
#end
pigment{color rgb 1}
finish{ambient 10
}
rotate <-20,15,0>
translate <5, 10, -10>
}
#end
camera {
location <0, 5, -5>
look_at <0, 0, 0>
}
#if (Reflector)
plane{
x,-15
pigment{color rgb 6}
rotate y*10
}
#end
plane {
y, -1
texture {
pigment {
gradient x
color_map {
[0.0 rgb <0.6, 0.4, 0.4>]
[0.5 rgb <0.2, 0.6, 0.8>]
[1.0 rgb <0.6, 0.4, 0.4>]
}
scale 4
rotate -45*y
}
#if (Scenetype=2)finish{reflection LightIntensity_onSurfaces_on_floor
montecarlo{mc_reflect{1 1 1 LightSoftness_onSurfaces_on_floor}}}#end
normal{
granite 0.6
scale 1.75
}
}
}
box {
-1, 1
scale <1,0.999,1>
texture{
pigment {
gradient y
color_map {
[0.0 rgb <0.9, 0.1, 0>/8]
[1.0 rgb <0.9, 0.1, 0>]
}
scale 2
translate -y
}
finish {
brilliance 1.0
phong 0.5
phong_size 40
specular 0.5
roughness 0.05
metallic 1
reflection {
0.5
1.0
fresnel on
falloff 1.0
exponent 1.0
metallic 0.9
}
#if (Scenetype=2)reflection LightIntensity_onSurfaces
montecarlo{mc_reflect{1 1 1 LightSoftness_onSurfaces}}#end
conserve_energy
}
normal {
granite 0.15
scale 2
}
}
rotate 25*y
translate <-3.25,0,2>
}
sphere {
0,1
texture {
pigment {
bozo
color_map {
[0.0 rgb <1,1,0>]
[1.0 rgb <0,0,2>]
}
scale 0.2
}
finish {
phong 0.25
phong_size 70
specular 0.65
roughness 0.005
brilliance 0.4
#if (Scenetype=2)reflection LightIntensity_onSurfaces
montecarlo{mc_reflect{1 1 1 LightSoftness_onSurfaces}}#end
}
}
translate <0,0,3>
}
torus {
1.0,
0.25
texture {
pigment {
gradient x
color_map {
[0.0 rgb <1,0,1>/1]
[0.3 rgb <1,0,1>/4]
[0.6 rgb <1,0,1>/2]
[1.0 rgb <1,0,1>/1]
}
scale 0.25
warp {
turbulence 0.25*x
}
}
finish {
phong 0.5
phong_size 25
specular 0.15
conserve_energy
diffuse 0.8
brilliance 1.0
#if (Scenetype=2)reflection LightIntensity_onSurfaces montecarlo{mc_reflect{1
1 1 LightSoftness_onSurfaces}}#end
}
}
translate <1.75,-0.75,-1.75>
}
cone {
-y,2,
2*y,0
material {
texture {
pigment {
color Col_Glass_Orange
}
finish {F_Glass3 ambient 0
}
}
interior {I_Glass}
}
translate <4,0,3>
}
cylinder {
<-2,-0.5,-2>, <0,-0.5,0>, 0.5
texture {
pigment {
dents
color_map {
[0.0 rgb <1,1,0>/2]
[0.5 rgb <1,1,0>]
[1.0 rgb <1,1,0>/2]
}
scale 1/4
}
normal {
crackle 1.5
scale 1/4
}
#if (Scenetype=2)finish{reflection LightIntensity_onSurfaces
montecarlo{mc_reflect{1 1 1 LightSoftness_onSurfaces}}}#end
}
translate <-1,0,-1>/2
}
Post a reply to this message
Attachments:
Download 'light-chalange_settings.jpg' (132 KB)
Preview of image 'light-chalange_settings.jpg'
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Christian Froeschlin <chr### [at] chrfrde> wrote:
> I wasn't quite sure whether not changing the objects meant
> you couldn't add any object to the scene. Using radiosity is
> a bit sad if the environment is completely black, so I added
> a blueish dome with ambient > 0 around the scene, which I
> suppose is still in the spirit of lighting the thing.
This makes sense -- and I appreciate you doing so. My use of radiosity usually
results in poor-to-average results, so I appreciate hearing ideas like this.
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Wow, thanks for your detailed analysis! You've got some great points, here.
"H. Karsten" <h-karsten()web.de> wrote:
> First is to understand the classic limitations and then making the decision,
> using the classic way, ore the classic way with further techniques, or using
> progressive techniques.
Yes, I agree. I've been trying to study basic lighting from a beginner's
photography standpoint (three-point lighting, etc.) but I don't always see good
results when translating this to my scenes.
> Your scene contains objects, heaving the "ambient" setting
> set to "0.1" try out, to set it to "0" and using other
> light-sources (very small values in power, using light fading
> and make it "shadowless". With this technique, you can try to
> setup reflecting light, coming from important, and big
> surfaces, illuminating other objects.
If I understand you correctly, the 'reflecting lights' are shadowless light
sources with low values that emulate inter-reflected light from other objects?
For example, if I have a scene with a red car, I might place a red shadowless
light near the car to 'help' cast scattered light...? It seems you'd have to be
careful not to allow the light to shine back on the object you're emulating.
(Or, perhaps I've misunderstood what you're trying to get across.)
> A basic rule is: Only the main light has a shadow. More then
> one main shadow is something, a professional photographer
> would never except. (For a normal setup)
Interesting! So, in a real photography setting, how do you add a light source
that doesn't cast a shadow?
Thanks for all your comments!
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Am 16.06.2010 06:46, schrieb H. Karsten:
> (Path-tracing, by using MC-Pov)
You may notice that the MC-Pov results are darker than the
POV-Ray+radiosity results.
This is actually due to a bug in MC-Pov, as I demonstrated in
<news://news.povray.org:119/4b093e4b@news.povray.org>, which causes the
diffuse brightness of objects to be reduced by an estimated 50%.
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