Thank you so muche Dave. I think that if the plane is not visible, it's a problem with normals.... me too, I tried to export without MCX. It's ok in FSX. maybe a problem with MCX. Just a question (again ... lol) : Why when I create a constraint for the bones, like "follow track" on curve, my bones go away ? It's a problem which I can't solve ... I must replace it in a good way... Sometimes, my plane turn or deforms ... It's painful .. Thank you for your help !