OK. This goes a bit too far for my simple understanding ;-)

As far as I can tell, the pattern seems not to be bugged, but that is 
for specialists to confirm. I have always used it to full satisfaction 
and complete agreement with the the documentation. However, isosurfaces 
being a bit more complex than height_fields, the tuning of the 
parameters is a bit more complex too.

I finally arrived at a correct render by using a negative direction of 
slope. I don't know why in earlier tests I did not get it right, 
probably I did other things wrong. I have still to test it further but 
as soon as I have a correct image I shall post it together with the 
pattern code used.

Thanks for the discussion! It always helps to clear the mess.

Thomas

On 4-7-2013 0:35, Le_Forgeron wrote:
> Le 03/07/2013 16:19, Thomas de Groot nous fit lire :
>>
>> Yes. Note that the documentation says the use 0.0, 0.5 for Lo_slope and
>> Hi_slope permits the texture_map to be used from 0 to 1.
>
> the default 'slope { <vector> }' is already in [0;1)
>
> when used with 'slope { <vector>, Low, High }', I'm afraid it's bugged,
> or I did not understood the text correctly.
>
> 1. parser transforms Low & High in Low, Range
> 2. pattern transforms value to (value-Low)/Range
> (original value is the angle in 0--1 : 0 is the opposite of the vector's
> direction, 1 is the same direction as the vector)
>
> 0 become -Low/Range
> 1 become (1-Low)/Range
>
> and then the usual modulo 1.0 is applied (unless altitude is present).
>
> So, ... 0.0 , 0.5 would transform 0 in 0, and 1 in 2. The 0, 0.5 give
> full range for *heighfield* (only) because there is no overhangs on
> heightfield. (but there is for isosurface, so better stay away from Low,
> High)
>
> I was hoping to have grass at the low part of map, but maybe you should
> reconsider and it might be easier to have grass near 1, and rock at 0.
>
> (and with altitude weighted as 1/4 (and slope at 3/4), the grass/soil
> might start at 0.6... but once again, I feel that Lower & Upper might be
> bugged, or not ? :
>
> 1. parser transforms Lower & Upper in Lower, Range
> 2. pattern transforms value to (value - Lower)/Range
> (original value is the oriented length of the projection of the point
> coordinate on the *normalised* vector of altitude (from origin)(yep,
> length of altitude is irrelevant, excepted for weight with slope)
>
>

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