@Vincebagna: ça yest! je me suis inscrit. Passionnant. Merci pour tout, à bientôt.

@Miss Nancy: Thanks a lot for this cursive and luminous definition. In four days of hard work reading forums and tutorials, it's the first time I see so a comprehensive explanation. I feel the temptation to compare ambiant occlusion with the old french hand-kiss where the knight's lips must reach the lady's silky glove the closest as possible, but without touching it physically.
So, I kiss your hand, My Lady.

Friendly, locusSolus.