[bav]

Нашел в исходниках объяснение значений в векторе vertexData:

/**
 * Updates the vertex data. All vertex properties are contained in a single Vector, and the order is as follows:
 * 0 - 2: vertex position X, Y, Z
 * 3 - 5: normal X, Y, Z
 * 6 - 8: tangent X, Y, Z
 * 9 - 10: U V
 * 11 - 12: Secondary U V
 */
public function updateData(data : Vector.<Number>) : void
{
    ...
}