Hallo. I begin to render lego with pov-ray. I am use Pov-Ray 3.7 because it use
multi core computer. And I use HDR lightning.
But I have problem. When I use HDR lighning a can't config it. I want floor
like this one: http://www.brickshelf.com/cgi-bin/gallery.cgi?i=4739403.
Can somebody help me how to do it?

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Le 04/10/2011 08:50, Stan a écrit :
> Hallo. I begin to render lego with pov-ray. I am use Pov-Ray 3.7 because it use
> multi core computer. And I use HDR lightning.
> But I have problem. When I use HDR lighning a can't config it. I want floor
> like this one: http://www.brickshelf.com/cgi-bin/gallery.cgi?i=4739403.
> Can somebody help me how to do it?
> 
> 
I do not know HDR lightning (excepted you need a picture for the
"skysphere"... sort of).

The image provided as example is probably using some area light (the
shadow at the extrem right are marked with typical degrees. At least a 3
steps area light was used).
Correlated with the shadow on the extrem left, it seems the area light
was a 3x3.

It was above and a bit in front of the construct. Mainly above, just a
bit in front. the up/front ratio probably being between 5 and 10 (so,
could be <0,100,-10> (if center of picture is <0,0,0>, y is up, and z is
deeper)  and the actual height / size of area light ratio not too high
either (maybe around 20: for a position at <0,100,-10>, the area light
might be 5 unit large or more

The floor is basically a partially reflective plane, with a bit of
diffuse and maybe some ambient. Rules of realism: the 3 terms adds to 1.
(finish { reflection a diffuse b ambient c } , with a+b+c =1.0)

Ambient is low (0.1 ?), reflection high (0.7 ?), diffuse get the remains.

analysis of the shadow on the extrem left on the construct itself seems
to indicate that the center of the area light might indeed be after the
very start of the construct (by a small bit)

There might/should be some filling lights (with far less strength)
around the construct (front/sides), to get some details more visible.
there seems to have one such light on the left-side of the construct, as
can be inferred by the weak shadow projected by the exhaust-pipe on the
rear-tank (right side of the picture).
Another in front is possible (if the rear-tank is also showing the weak
shadow of the crank on its front-side)

Yet, no HDR needed.

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Am 04.10.2011 08:50, schrieb Stan:
> Hallo. I begin to render lego with pov-ray. I am use Pov-Ray 3.7 because it use
> multi core computer. And I use HDR lightning.
> But I have problem. When I use HDR lighning a can't config it. I want floor
> like this one: http://www.brickshelf.com/cgi-bin/gallery.cgi?i=4739403.
> Can somebody help me how to do it?

It might be a good idea to post an image (in povray.binaries.images) of 
what you've come up with so far, making it easier to diagnose what your 
problems are.

Taking a wild guess, you possibly see reflections of the HDR background 
on the floor and don't want those. In that case, instead of using a 
sky_sphere for the HDR background you can use a very large sphere with 
the "no_reflection" keyword.

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> Taking a wild guess, you possibly see reflections of the HDR background
> on the floor and don't want those. In that case, instead of using a
> sky_sphere for the HDR background you can use a very large sphere with
> the "no_reflection" keyword.
Thank you, but i found it)
http://xmages.net/storage/10/1/0/2/5/thumb/thumb_9fcaddc5.jpg
This is my render of lego set.
The problem I have is floor.
When I don't use HDR I can change it reflection, brilliance and other. But when
I use HDR floor is just white or gray(

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Stan wrote:

> When I don't use HDR I can change it reflection, brilliance and other. But when
> I use HDR floor is just white or gray(

What exactly do you mean by "use HDR", are you talking
about a HDR environment or outputting HDR images? How do
you use it, can you show a piece of code?

The floor object itself should remain a white reflecting plane,
no change change required whether you use HDR or not.

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Am 04.10.2011 22:34, schrieb Stan:
>
>> Taking a wild guess, you possibly see reflections of the HDR background
>> on the floor and don't want those. In that case, instead of using a
>> sky_sphere for the HDR background you can use a very large sphere with
>> the "no_reflection" keyword.
> Thank you, but i found it)
> http://xmages.net/storage/10/1/0/2/5/thumb/thumb_9fcaddc5.jpg
> This is my render of lego set.
> The problem I have is floor.
> When I don't use HDR I can change it reflection, brilliance and other. But when
> I use HDR floor is just white or gray(

What you describe doesn't sound like you're using POV-Ray directly. Are 
you perhaps using a 3rd party tool to convert your Lego set to POV-Ray 
format, and using HDR is one option of that tool?

If so, please consult the documentation of that tool; if there's no way 
to do that with the tool, you may need to manually edit the generated 
.pov file before rendering.

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> What you describe doesn't sound like you're using POV-Ray directly. Are
> you perhaps using a 3rd party tool to convert your Lego set to POV-Ray
> format, and using HDR is one option of that tool?
>
Yes I am using L3p tool. It converts *.ldr(ldraw format file) to Pov-Ray
But I discribe lighting manual.


#declare LDRAW_RAD_LEVEL = 5; // 5=final
#declare LDRAW_MTL = 256;
#declare INDEXOFREFRACTION=1.52;
#declare LDRAW_RAD_NORMAL = off;
#declare LDRAW_RAD_MEDIA = off;

#include "rad_def.inc"
global_settings {
  assumed_gamma 1.4
  max_trace_level LDRAW_MTL
  adc_bailout 0.01/2
  radiosity {
    Rad_Settings(LDRAW_RAD_LEVEL, LDRAW_RAD_NORMAL, LDRAW_RAD_MEDIA)
  }
}

    sphere {
   <0,0,0>,10000
   pigment {
     image_map { hdr "entrance1_color" once interpolate 2 map_type 1 }
   }
   finish {  emission 1 }
   hollow
   no_image
   no_reflection
          no_shadow
 }

I use radiosity, and HDR lighting. I add Hdr image to sphere.

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Am 05.10.2011 10:03, schrieb Stan:
>
>> What you describe doesn't sound like you're using POV-Ray directly. Are
>> you perhaps using a 3rd party tool to convert your Lego set to POV-Ray
>> format, and using HDR is one option of that tool?
>>
> Yes I am using L3p tool. It converts *.ldr(ldraw format file) to Pov-Ray
> But I discribe lighting manual.
(*snip*)

Looks ok to me so far; what texture are you using (or trying to use) for 
the floor?

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> Looks ok to me so far; what texture are you using (or trying to use) for
> the floor?

// Floor:
object {
 plane { y, floor_height hollow }
 pigment { rgb <0,0,0> }
 finish {
         ambient 0.
         diffuse 1
                 brilliance 5
                 metallic
                 specular 0.80
                 roughness 1/100
                 reflection 0.9

        }
}

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Am 05.10.2011 18:18, schrieb Stan:
>
>> Looks ok to me so far; what texture are you using (or trying to use) for
>> the floor?
>
> // Floor:
> object {
>   plane { y, floor_height hollow }
>   pigment { rgb<0,0,0>  }
>   finish {
>           ambient 0.
>           diffuse 1
>                   brilliance 5
>                   metallic
>                   specular 0.80
>                   roughness 1/100
>                   reflection 0.9
>
>          }
> }

Are you aware that this surface will never catch any shadows, because it 
is purely reflective (due to the black pigment)?

Also note that with HDR (i.e. radiosity-based) illumination, the 
brilliance, specular and roughness parameters have no effect.

You will also never get sharp shadows in this manner (though you can 
improve the sharpness of the shadows by specifying a low maximum_reuse 
value, of course at the cost of rendering time).

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