Fabien,

if I have understood you correctly you're saying that finish is
view-dependent, while pigment and normal are not. I have tried several times
to explain why that is not true, but apparently have failed.

I will now try to explain it using some clearer expressions. I will use
"property" contra "appearance". These should not easily be mixed up.

In the pigment you specify the colour(s) of your object. If you make a
sphere with a white pigment, then a property of the sphere is that it is
white. Even if your object is lit by a red light_source only, the colour
property of the sphere is *still* white. The *appearance* however, is *red*
(and very dark red where it is in shadow).

Note that the surroundings don't affect the property of the object, but they
do affect the appearance.

Now to the normal. A property of an object can be it's slope at a given
point. This slope is independent on the surroundings (lights, camera, etc.).
However, the *appearance* of the slope is dependent on many things which I
will not go into details with here.

In the finish you specify many properties of the object. Ambient, diffuse,
the amount of reflection, highlights, and many other things. The values you
specify are the properties of the object. They are independent of the
surroundings (view-independent). Only the *appearance* is dependent on the
surroundings.

When you want to measure the reflected rays for an object, that is related
to the appearance, not the property of the object.

So for the pigment you want to measure a property.
And for the normal you want to measure a property.
But for the finish you want to measure the appearance!!!

So as I have said many times before, you can't compare like that.

Rune
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