| The ratio of section′s area of 3D object may describ e the geometric structure and it is a index in common use. The calculation meth od is different in different coding. This paper presents a way for calculating t he ratio of section′s area of 3D object in octree coding. The two kinds of meth ods based on the type of section′s axis are discussed. The one is the axis perp endicular to coordination axis and the other is in any direction. The two method s need the transformation from octree to section quadtree. The first method dire ctly traverse the octree, the second is to rotate and move the octree for that t he axis of section coincide with coordination axis and then it produces a new oc tree,then produces section quadtree by the first method. The ratio of section′s area is calculated from section quadtree. |
