Le 08/12/2014 09:20, Thomas de Groot a écrit :
> On 7-12-2014 18:28, Le_Forgeron wrote:
>> For a solution based on toroidal (original post), the solution is with
>> dist_exp 200 (or any big enough value) to neglect the effect of depth,
>> or changing the cylindrical to a pigment that has no influence due to
>> depth , value 1 at 0, value 0 at -1 and 1: it's planar !!!
>>
> [snip]
>>
>> Strictly speaking, dist_exp is cheating. Planar is not.
>>
> 
> Interesting. I wondered how to use dist_exp as the docs are not very
> clear on that issue and I did not know what it really represented.
> 

Not clear ? Not extensive, maybe confusing, but seems clear:
 to cite the wiki:

 With the cylindrical, spherical and toroidal warps you can wrap
checkers, bricks and other patterns around cylinders, spheres, toruses
and other objects. In essence, these warps use the same mapping as the
image maps use.

However it does 3D mapping and some concession had to be made on depth.
This is controllable by dist_exp (distance exponent). In the default of
0, imagine a box <0,0> to <1,1> (actually it is <0,0>,
<dist^dist_exp,dist^dist_exp>) stretching to infinity along the
orientation vector. The warp takes its points from that box.


> Thanks indeed
> 
> Thomas


-- 
Just because nobody complains does not mean all parachutes are perfect.

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On 8-12-2014 9:53, Le_Forgeron wrote:
> Not clear ? Not extensive, maybe confusing, but seems clear:
>   to cite the wiki:
>
>   With the cylindrical, spherical and toroidal warps you can wrap
> checkers, bricks and other patterns around cylinders, spheres, toruses
> and other objects. In essence, these warps use the same mapping as the
> image maps use.
>
> However it does 3D mapping and some concession had to be made on depth.
> This is controllable by dist_exp (distance exponent). In the default of
> 0, imagine a box <0,0> to <1,1> (actually it is <0,0>,
> <dist^dist_exp,dist^dist_exp>) stretching to infinity along the
> orientation vector. The warp takes its points from that box.
>

Indeed. I understood the meaning :-) but I assumed that the distance was 
to be used /within/ the boundary of the minor radius, so in my trials it 
was always rather small.

Thomas

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On 08.12.2014 9:16, Thomas de Groot wrote:

> Well, as you realize, seen from a planet's surface, the basic shape is
> not really important. I could also just use a cylinder or a box within
> the camera view ;-)

Oh I see, you want to render an inside view ;)

In that case the shape is indeed not so important ... absorption is
so high (at visible wavelengths) that most light you see from the Milky
Way is from our "local" galactic neighborhood only (~ 1 kpc radius).

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