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Hello Forum,
I recently posted about about trying to simulate bubbles in a tube and received
a lot of great feedback on my scripting approach! I've made changes to my
previous setup to clean it up, but have two outstanding questions/issues. The
first is on the area_light function, and the second is an issue that I am having
when rendering my new script.
1) Area_light:
In my last discussion, I received some great feedback on the area_light
function, but I am still having some issues with it in concept. In my script, I
want to create a diffuse backlight for my scene. I am trying to recreate the
effect of having a bright light shining through transparent objects directly
into my camera. to do this, I am beginning by defining an area_light with the
following characteristics:
- parallel to the X-Y-plane
- centred on the Z-axis
- with dimensions 160x200 (x,y)
- I then want the center translated to position <0,0,100>
- 100 x 100 lights array
- white light
Firstly, can somebody confirm that I have defined this correctly, below?
light_source {
<0, 0,100>
color White
area_light <-80, -100, 0>, <80, 100, 0>, 100, 100
adaptive 1
jitter
}
Next, if I understand this correctly, I would not actually see my light source
shining like I would in real life, and instead need to create an object onto
which I put the area source if I want that realistic studio light panel look.
To do this, I have used the looks_like function, defining a white rectangular
box that will act as my light panel. Can somebody confirm that this has been
implemented correctly?
#declare light_box = box{ <-80,-100,0>, <80,100,2>
pigment{color White}
} //end light box
light_source {
<0, 0,100>
color White
area_light <-80, -100, 0>, <80, 100, 0>, 100, 100
adaptive 1
jitter
looks_like { light_box }
}
Is what I'm trying to do make sense to create this diffuse, bright,
backlighting effect?
If my area_light dimensions do not match the dimensions my defined
looks_like{} object, will the area light stretch to accommodate the defined
object?
2). Rendering Issue and the appearance of dark regions after animation
rendering:
My next question pertains to a rendering issue I have run into. I reformatted
my previous script with the generous input of forum users. Here I have defined
each region of my setup in a more efficient manner that I was perviously. In my
attached file, I am simulating air bubbles trapped in a gel housed within a
glass tube. Outside of this tube is a cylinder of water and then a cylinder of
plexiglass.
When I first rendered my setup, everything was looking good, and so I decided to
run it as an animation, rotating the bubbles around Y axis. However, when I ran
the animation, the boundary between the glass and water appeared to be speckled,
which immediately made me think of an overlapping surface issue. I addressed it
by adding an "epsilon" to the radius of my water cylinder's inner surface and
ran it again. While the speckled surface issue was resolved, a large portion of
my cylinder is being rendered as a dark region, and this region will not go away
no matter what I do, and I cannot recreate the original bright region. I also
tried turning off the fade and this did not help.
Can anyone help me troubleshoot this issue?
Thank you all for your support and insights!
Sincerely,
Bubble_person
* I have attached my code here, below, because I cannot figure out how to add a
photo and my script. Sorry for the long post!
//Files with predefined colors and textures
#include "colors.inc"
#include "glass.inc"
#include "stones.inc"
global_settings { max_trace_level 50}
#declare epsilon = .0001;
#declare light_loc_x = 0;
#declare light_loc_y = 0;
#declare light_loc_z = 90;
#declare tube_base = -55;
#declare tube_height = 92;
#declare tube_rinner = 13;
#declare tube_router = 16;
#declare tube_lip_width = 2;
#declare tube_rotation_x = 0;
#declare tube_rotation_y = 2*clock;
#declare tube_rotation_z = 0;
#declare water_router = 25.4;
#declare plexi_router = 31.75;
#declare gel_height = 0.9*tube_height;
#declare bubble_r = 0.8;
#declare bubble_ior = 1.0;
//Place the camera
camera {
location <000,000,-500> //Camera location
look_at <0,0,1> //Where camera is pointing
angle 15 //Angle of the view--increase to see more, decrease to see less
}
//Ambient light to "brighten up" darker pictures
global_settings { ambient_light White }
//Set a background color
background { color Black }
// Set up light source from box
#declare light_box = box{ <-80,-100,0>, <80,100,2>
pigment{color White}
} //end light box
light_source {
<light_loc_x, light_loc_y,light_loc_z>
color White
area_light <-80, -100, 0>, <80, 100, 0>, 100, 100
adaptive 1
jitter
looks_like { light_box }
}
//=====================================================================================
// Creating bubbles that go into gel
//=====================================================================================
// Create Bubbles
#declare MatBubble =
material {
texture {
pigment {color rgbt<.99,.99,.99,0.98>}
normal { bumps 0 scale 0.025 }
finish { phong .001 }
} // end of texture
interior{
ior bubble_ior
dispersion 1.01 // this simulates dispersion caused refraction
dispersion_samples 7
fade_power 1001 //(0=off) (realistic: 1~2, >=1000 ->realistic
exponential attenuation function will be used!)
} // end of interior
} // end of material
// Add Bubble Definitions Here:
#declare Bubble_5 =sphere{ <3.94,-7.554,-4.927>, (bubble_r)
material{MatBubble}
} //end sphere (bubble)
#declare Bubble_4 =sphere{ <-1.53,35.605,-2.926>, (bubble_r)
material{MatBubble}
} //end sphere (bubble)
#declare Bubble_3 =sphere{ <-1.271,40.873,2.981>, (bubble_r)
material{MatBubble}
} //end sphere (bubble)
#declare Bubble_2 =sphere{ <2.972,-36.206,-1.126>, (bubble_r)
material{MatBubble}
} //end sphere (bubble)
#declare Bubble_1 =sphere{ <8.863,-12.984,3.351>, (bubble_r)
material{MatBubble}
} //end sphere (bubble)
union {
// Add Union here
object {Bubble_5}
object {Bubble_4}
object {Bubble_3}
object {Bubble_2}
object {Bubble_1}
rotate <tube_rotation_x,tube_rotation_y,tube_rotation_z>
}
//=====================================================================================
//Creating Glass Tube
//=====================================================================================
//create hollow cylinder
#declare GlassTube =
merge{
difference{
//Create single cylinder
cylinder { <0,(tube_base-epsilon),0>, <0,tube_height,0>, tube_router
} // end cylinder
cylinder { <0,(tube_base-2*epsilon),0>, <0,tube_height+epsilon,0>,
tube_rinner
} // end cylinder
} // End difference (hollow cylinder)
//create hollow half-sphere
difference{
difference{
//Create single cylinder
sphere { <0,0,0>, tube_router } // end sphere
sphere { <0,0,0>, tube_rinner} // end sphere
} // End difference (Hollow Sphere)
box{ <-2* tube_router ,0,-2* tube_router >,
< 2*tube_router , 2*tube_router ,2* tube_router >
} // End Box
translate<0,tube_base,0>
} // End Difference (Half-Sphere)
// create Lip torus at top of tube
torus { (tube_router+ tube_rinner)/2, tube_lip_width
translate <0,tube_height,0>
} // End Torus (Tube Lip)
material{
texture { pigment{ color rgbt<.99,.99,.99,0.99>}
normal { bumps 0 scale 0.025 }
finish { phong .99 }
} // end of texture
interior{ ior 1.56
dispersion 1.0 // this simulates dispersion caused
refraction
dispersion_samples 7
fade_power 1001 //(0=off) (realistic: 1~2, >=1000
->realistic exponential attenuation function will be used!
caustics 0.0
} // end of interior
} // end of material
rotate<tube_rotation_x,tube_rotation_y,tube_rotation_z>
} // End Merge (Full tube)
GlassTube
//=====================================================================================
// Creating Gel to fill Glass Tube with voids for the bubbles
//=====================================================================================
// Creating gel to fill glass
#declare GelCyl =
merge{
sphere { <0,tube_base,0>, tube_rinner-epsilon} // end sphere
cylinder{<0,tube_base,0>, <0,gel_height,0>, tube_rinner-epsilon}// end
cylinder
material{
texture { pigment{ color rgbt<.99,.99,.99,0.98>}
normal { bumps 0 scale 0.025 }
finish { phong .001 }
} // end of texture
interior{ ior 1.405
dispersion 1.0 // this simulates dispersion
caused refraction
dispersion_samples 7
fade_power 1001 //(0=off) (realistic: 1~2, >=1000
->realistic exponential attenuation function will be used!
caustics 0.0
} // end of interior
} // end of material
} // end merge (gel matrix)
GelCyl
//=====================================================================================
// Creating Water Cylinder around tube
//=====================================================================================
#declare WaterCyl =
difference{
cylinder{
<0,tube_base-tube_router,0>,<0,tube_height*.8,0>, water_router} //End outer
cylinder
merge{
cylinder{<0,tube_base,0>, <0,tube_height+epsilon,0>, tube_router-epsilon} //
end cylinder for glass tube
sphere{<0,tube_base,0>, tube_router-epsilon} // end sphere (tube bottom)
} //end merge (glass tube inside of water
material{
texture { pigment{ color rgbt<.99,.99,.99,0.98>}
normal { bumps 0 scale 0.025 }
finish { phong .001 }
} // end of texture
interior{ ior 1.33
dispersion 1.0 // this simulates dispersion
caused refraction
dispersion_samples 7
fade_power 1001 //(0=off) (realistic: 1~2, >=1000
->realistic exponential attenuation function will be used!
caustics 0.0
} // end of interior
} // end of material
} // End difference of outer water tube
WaterCyl
//=====================================================================================
//Creating Plexiglass Cylinder holding water
//=====================================================================================
#declare PlexCyl =
difference{
cylinder{<0,tube_base-tube_router,0>,<0,tube_height*.9,0>, plexi_router} //End
outer cylinder
cylinder{<0,tube_base-tube_router-epsilon,0>,<0,tube_height*.9+epsilon,0>,
water_router+epsilon} //End outer cylinder
material{
texture { pigment{ color rgbt<.99,.99,.99,0.98>}
normal { bumps 0 scale 0.025 }
finish { phong .001 }
} // end of texture
interior{ ior 1.495
dispersion 1.0 // this simulates dispersion
caused refraction
dispersion_samples 7
fade_power 1001 //(0=off) (realistic: 1~2, >=1000
->realistic exponential attenuation function will be used!
caustics 0.0
} // end of interior
} // end of material
} // End difference of outer water tube
PlexCyl
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