Le 16-02-16 20:16, Sven Littkowski a écrit :
> Hi, big thanks, so far. please let's continue.
>
> I used "760.0*x*0.7   // Color?" because you wrote: "AxleRadius*x*0.7".
> I don't need a red light, so I will change it. :-)
>
> Right after you wrote "257,33", that is why I placed them right after,
> too. What are these two numbers actually about, or for?

They define how many samples there are along the axis of the area_light

> And where exactly to place them? After the vectors of the area_light as
> replacement for "3,3"?
Yes.
>
> Vectors of the area_light:
> < -1000.0, -1300.0, 0.0 > < 1000.0, -1300.0, 5000.0 >
> What exactly do they describe? The illuminated area? Or the area
> (rectangle) in which all lights are in? I might have to make some
> changes to those two vectors, based on your answer. :-)

Those define the physical dimention and orientation of the area_light 
basic rectangle.
In your case, you want it to be parallel to the axis of the habitat. 
Assuming that that axis is along the Z axis, the large value must be 
along the Z axis. The short axis should be along the X or Y axis, 
depending on whitch is the most convenient for your situation.

The effective rectangle is shifted so that it's center point sit at the 
light's location. So, the rectangle si centered on the light's location 
and extend +- half the dimention around that point.

>
> At the moment, I have this as light system, but the resulting image is
> just showing a distant gray ring:
> ---------------------------
>
> #if(IlluminationType="Lights")
>   #declare MyLight = union
>   {
>    light_source
>    {
>     5000*z                   // Location

As it is now, the light is located at the far extremity of the cylinder.
Change to 2500*z so that it's centered along the length of the cylinder.

>     rgb < 1.00000, 0.98824, 0.88235 > // Color
OK, a somewhat warm looking light colour.
>     area_light               // Type
>     5000*z 760*0.7*x 257, 33 // Vectors
OK.
>     adaptive 0               //
Make it render as fast as possible.
>     area_illumination on     //
>    }
>    cylinder
>    {
>     0, 5000.0*z, 760.0
>     pigment
>     {
>      radial
>      color_map
>      {
>       [ 0.00 rgb  0.5 ]
>       [ 0.05 rgbf < 0.8, 0.5, 0.2, 1.0 > ]
>       [ 0.10 rgbf 1.0 ]
>       [ 0.40 rgbf 1.0 ]
>       [ 0.45 rgbf < 1.0, 0.7, 0.5, 1.0 > ]
>       [ 0.50 rgb  0.5 ]
>      }
As radial rotate around the Y axis, you need to rotate it 90° around the 
X axis.
   rotate 90*x
>      rotate 180*z
May need to be adjusted so that the opening is facing up or down.

>     }
> //   interior_texture  // not yet in place. But shouldn't that cylinder
> be hollow then?

interior_texture is entirely optional.
Don't need to add hollow. hollow only enable the object to contain some 
media or fog, nothing else.

>     translate < 0.0, -10.0, 0.0 >
>    }
>   }
> #end
>
> ----------------------------------------
>
>
Quotted from the documentation:

"The radial pattern is a radial blend that wraps around the +y-axis. The 
color for value 0.0 starts at the +x-direction and wraps the color map 
around from east to west with 0.25 in the -z-direction, 0.5 in -x, 0.75 
at +z and back to 1.0 at +x. Typically the pattern is used with a 
frequency modifier to create multiple bands that radiate from the y-axis."

In this case, we only want the pattern to repeat once around the cylinder.


Alain

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