This is View3D, version 3.2, a C program for the computation of geometric view factors. This version of View3D is included as part of the EnergyPlus installer package. The program utilizes a number of integration techniques to compute view factors between planar triangles or quadrilaterals in three dimensions.
The original version of this program was developed at the National Institute of Standards and Technology by George Walton and was in the public domain with this disclaimer:
This software was developed at the National Institute of Standards and Technology by employees of the Federal Government in the course of their official duties. Pursuant to title 17 Section 105 of the United States Code this software is not subject to copyright protection and is in the public domain. These programs are experimental systems. NIST assumes no responsibility whatsoever for their use by other parties, and makes no guarantees, expressed or implied, about its quality, reliability, or any other characteristic. We would appreciate acknowledgment if the software is used. This software can be redistributed and/or modified freely provided that any derivative works bear some notice that they are derived from it, and any modified versions bear some notice that they have been modified.
This modified version is made available under the BSD3 license in LICENSE.txt. Files that are not significantly modified contain only the NIST disclaimer and are in the public domain.