 |
|
|
|
|
|
| |
| |
|
|
|
|
| |
| |
|
|
> I once tried to render a similar scene on Luxrender, also unbiased. It
> too wasn't quite able to reproduce that same delicious Mental Ray
> dielectric shader effect. Does that mean the Mental Ray dielectric
> shader, while beautiful, does not correspond to reality?
I think it's just a matter of tweaking the colours, filter/transmit
parameters, reflection values, etc. But the problem is with unbiased
renderers it can take an age to go through this trial/error process if you
are trying to copy some effect.
I don't think that the Mental Ray shader is doing anything fundamentally
different to POV or Luxrender.
Post a reply to this message
|
|
| |
| |
|
|
|
|
| |
| |
|
|
scott escreveu:
> I think it's just a matter of tweaking the colours, filter/transmit
> parameters, reflection values, etc.
I gave up on that already. Lost lots of hours tweaking lots of
disparate parameters. At least there's not much of that with
physically-based renderers.
> I don't think that the Mental Ray shader is doing anything fundamentally
> different to POV or Luxrender.
Still, it seems to display some of the best glassware around. If it
requires this much tweaking, I wonder why so many users seem to get it
relatively easily in their renders.
--
a game sig: http://tinyurl.com/d3rxz9
Post a reply to this message
|
|
| |
| |
|
|
|
|
| |
| |
|
|
>> I don't think that the Mental Ray shader is doing anything fundamentally
>> different to POV or Luxrender.
>
> Still, it seems to display some of the best glassware around. If it
> requires this much tweaking, I wonder why so many users seem to get it
> relatively easily in their renders.
I suspect you can just do an "Insert -> Dielectric Shader" and the defaults
are all pretty accurate for glass.
For example, in POV you need to type reflection{ a,b fresnel on}. What do a
and b do in this situation, given that the fresnel equations should exactly
define the % reflection and % transmission?
Post a reply to this message
|
|
| |
| |
|
|
|
|
| |
| |
|
|
> So, I don't really think you're quite there yet if this render is any
> indication. I'm not really concerned with the shadows or caustics, but
> with the fact that the blue glass behind comes up with almost the same
> color after passing through the red glass:
Is this one better? I think the blue shows through better now (I used
colour picker in PSP to get the exact shade of red and blue from the
original image).
For me the hardest part is getting the lighting correct now, either the
torii are too bright or the floor is too dark in the reflections. Using
Fresnel should give 100% reflection around the edges of the torii, so I
don't know why the floor is coming out so dark.
Post a reply to this message
Attachments:
Download 'image2.jpg' (106 KB)
Preview of image 'image2.jpg'
|
|
| |
| |
|
|
|
|
| |
| |
|
|
scott escreveu:
>> So, I don't really think you're quite there yet if this render is any
>> indication. I'm not really concerned with the shadows or caustics,
>> but with the fact that the blue glass behind comes up with almost the
>> same color after passing through the red glass:
>
> Is this one better? I think the blue shows through better now (I used
> colour picker in PSP to get the exact shade of red and blue from the
> original image).
whoa! So much friggin' better! You truly nailed it, man! Right colors
and right smooth shadows and caustics! Only one of the light box
reflections in the blue torus is coming filtered red...
did you drop the media inside the torii? Post the changes, man! if you
feel like it, that is. It's not GPL'd... :D
> For me the hardest part is getting the lighting correct now, either the
> torii are too bright or the floor is too dark in the reflections. Using
> Fresnel should give 100% reflection around the edges of the torii, so I
> don't know why the floor is coming out so dark.
Perhaps going from .5 to 1 in the fresnel block? I think I go from 0 to
1 as is?...
BTW, it's not finished yet, but perhaps you'll want to play with it
sometime. Yet another take on another Mehran Moghtadai's mentalray render:
http://i35.tinypic.com/2ll20c0.jpg
the original:
http://en.wikipedia.org/wiki/File:Glass_is_Liquide.jpg
made in Blender with the reference picture as blue print and rendered in
Lux in, so far, 4 hours on a Core 2 Duo (at work :P)
Lighting is not quite the same but worse: he seems to have gone for
surrealism as the liquid inside seems to go beyond the glass sides, like
as if molten with it...
If you're interested, I may later convert it to pov format.
--
a game sig: http://tinyurl.com/d3rxz9
Post a reply to this message
|
|
| |
| |
|
|
|
|
| |
| |
|
|
> whoa! So much friggin' better! You truly nailed it, man! Right colors
> and right smooth shadows and caustics! Only one of the light box
> reflections in the blue torus is coming filtered red...
>
> did you drop the media inside the torii? Post the changes, man! if you
> feel like it, that is. It's not GPL'd... :D
> Perhaps going from .5 to 1 in the fresnel block? I think I go from 0 to 1
> as is?...
That's what I don't understand, Fresnel should determine the reflection %
based on the IOR and the angle, nothing else, I don't get what the other two
parameters do in this cae, or what I should set them to. I just use
reflection{1 fresnel on} for now - I hope that is physically correct.
Note this version below is not exactly the one that gave that image (I've
had a tweak with it this morning to try and get the floor reflection to
appear brighter). Anyway, here you go, for MCPOV:
#default { texture { pigment { color rgb 1 } finish { diffuse 1 ambient 0
montecarlo { mc_diffuse { 1 3 1 } } } } }
camera { angle 30 }
global_settings {
max_trace_level 100
adc_bailout 0.02
assumed_gamma 1.0
montecarlo{
mc_dof { mc_focal_distance 6 mc_lens_radius 0.002 }
}
}
// provide some ambient light...
sphere{ <0,0.5,0> 0.5
pigment {
gradient y
color_map {
[ 0.5 color rgb 0]
[ 0.8 color rgb 0 ]
[ 1.0 color rgb 1 ]
}
}
finish{ambient 2 diffuse 0}
translate <0,-0.5,0>
scale 1000
}
// background { rgb 0.0 }
#macro reflmat( fdcol )
texture {
pigment { color rgbt <0,0,0,1> }
finish {
diffuse 0 ambient .0
reflection{1 fresnel on}
conserve_energy
}
}
hollow
interior { ior 1.5 fade_color fdcol fade_power 2 fade_distance 0.002}
#end
// cena
union {
// chao
plane{ y 0
pigment { rgb 1 } finish { ambient .0 diffuse .99 }
}
// as duas semi-roscas: red (x) e blue (z)
union {
torus { 1.2,.16 reflmat( <0.15,0.45,1> ) rotate x*90
translate -y*.0 + x/3 }
torus { 2,.2 reflmat( <1,0.2,0.2> ) rotate x*90+y*90
translate -y*.4 }
translate -y/2
}
#local P1 = <-1,0,-1>;
#local P2 = < 1,0,-1>;
#local P3 = < 1,0,1>;
#local P4 = <-1,0,1>;
union{
triangle { P1,P2,P3
montecarlo { mc_portal { 6 4 1 1 } }
}
triangle { P1,P3,P4
montecarlo { mc_portal { 6 4 1 1 } }
}
#local d = 5; // Used to tweak the position of the light
scale d
translate y*4*d
translate x*0.35*d
pigment { rgb 1 }
finish { ambient 20 diffuse 0 }
}
rotate -y*30
rotate -x*30
translate z*6+y/5
}
Post a reply to this message
|
|
| |
| |
|
|
|
|
| |
| |
|
|
weird. You have no filter component in the pigment, but it still filters light
as the shadows show...
I think you could also drop the DOF to bring down render times... would plain AA
be faster?
Post a reply to this message
|
|
| |
| |
|
|
|
|
| |
| |
|
|
> weird. You have no filter component in the pigment, but it still filters
> light
> as the shadows show...
I have used fade_color inside the interior block to do the colouring.
> I think you could also drop the DOF to bring down render times... would
> plain AA
> be faster?
In MCPOV you get the DOF (and AA) for free. It's repeatedly sending rays
through the same pixel, the DOF just causes it to jitter the rays in a way
to simulate DOF rather than just plain AA.
Post a reply to this message
|
|
| |
| |
|
|
|
|
| |
| |
|
|
"scott" <sco### [at] scott com> wrote:
> > weird. You have no filter component in the pigment, but it still filters
> > light
> > as the shadows show...
>
> I have used fade_color inside the interior block to do the colouring.
o_o
It`s true! Never gave much thought to it. I thought fade_color would only
affect the color of the object, not its shadows...
> > I think you could also drop the DOF to bring down render times... would
> > plain AA
> > be faster?
>
> In MCPOV you get the DOF (and AA) for free. It's repeatedly sending rays
> through the same pixel, the DOF just causes it to jitter the rays in a way
> to simulate DOF rather than just plain AA.
True too. It`s already sending a multitude of rays anyway...
Post a reply to this message
|
|
| |
| |
|
|
|
|
| |
| |
|
|
scott schrieb:
> For me the hardest part is getting the lighting correct now, either the
> torii are too bright or the floor is too dark in the reflections. Using
> Fresnel should give 100% reflection around the edges of the torii, so I
> don't know why the floor is coming out so dark.
Looks to me like you're not getting the right illumination on your
floor, and that light intensity falls off drastically towards the
horizon...?
Post a reply to this message
|
|
| |
| |
|
|
|
|
| |
