Computing area of all facets in CGAL::Polyhedron_3

In this post I will show how to compute area of a facet in CGAL::Polyhedron_3.

ComputeFacetArea() Functor

ComputeFacetArea() is a thread-safe functor for computing the area of a given facet in a CGAL::Polyhedron_3. The facet must be a planar polygon with arbitrary number of sides. We need facet’s normal vector to compute it’s area. The facet normals must be be initialized using the ComputeFacetArea()’s constructor. The code for computing the facet normals is presented in this post: Computing normal of all facets in CGAL::Polyhedron_3.

Using ComputeFacetArea() Functor

Area of a facet f can be computed as double area = ComputeFacetArea(h);.

For most purposes, it is better to compute area of all facets once and cache them for later use. It is best to store the results in an associative container which associates the facet handle with the area. In the following example, I use PropertyMap which is a wrapper for std::set.

Downloads

ImportOBJ.h
PropertyMap.h
ComputeFacetNormal.h
ComputeFacetArea.h
TestComputeFacetArea.cpp
Venus.obj
ComputeFacetArea.zip


2 Comments
  • Ashwin Nanjappa Reply

    Glad to see all the blog posts, microscope and photos! 🙂

    • Saurabh Garg Reply

      Thanks Ashwin. Its nice hearing from you after a long time 🙂

      -Saurabh

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