On 8-5-2015 10:41, Stephen wrote:
> On 08/05/2015 08:54, Thomas de Groot wrote:
>
>> After testing, I can confirm that it is not possible to rotate a slope
>> pattern, in contrast to other patterns. Even more puzzling, I can
>> confirm that this is true too when applying the pigment and then
>> rotating the object: the pigment remains unchanged and does not rotate
>> with the object.
>>
>> I do not know if this is a bug or is intentional. If the latest case,
>> the documentation does not mention it while at the same time indicating
>> the use of Pigment Modifiers in the example.
>>
>> I believe we need the voice of an expert now.
>>
>
> And I thought that you were the expert. ;-)

I am sorry to disappoint you ;-)

>
> My understanding of the slope pattern is that the colour (value) is
> dependant on the normal of the point on the object being tested and the
> direction vector. So the pigment is tied to the object's shape. To
> rotate the patern, rotate the direction vector.
>
>> The slope value at a given point is dependent on the angle between the
>> <Direction> vector and the normal of the surface at that point. For
>> example:
>> - When the surface normal points in the opposite direction of the
>> <Direction> vector (180 degrees), the slope is 0.0.
>> - When the surface normal is perpendicular to the <Direction> vector
>> (90 degrees), the slope is 0.5.
>> - When the surface normal is parallel to the <Direction> vector (0
>> degrees), the slope is 1.0.
>

Yes that is my understanding too, up to a point. What mystifies me is 
when an object is patterned with slope and then rotated: why is the 
pattern not following the rotation of the object? That is not correct to 
my understanding.

-- 
Thomas

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