jasondegraw / view3d

View3D is a C program for the computation of geometric view factors.

View3D

View3D is a C program for the computation of geometric view factors.

This is View3D 4.0, a C language program for the calculation of geometric view factors. It 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. This version is released subject to the terms of the GNU GPL and is not in the public domain. Any files that have not been substantially modified are labeled as such and include the original NIST disclaimer.

Documentation

This version is not intended to behave differently than versions 3.2 or 3.3.1. The documentation for those programs is available from a number of sources:

• Version 3.2 has been included with the US Department of Energy's EnergyPlus for some time. To install the program and documentation, during the main EnergyPlus installation select the optional view factor installation. EnergyPlus is available at www.energyplus.gov.
• Documentation for version 3.3.1 is available here: www.personal.psu.edu/jwd131/software/v3d33/manual/view3d33manual.html.

Installation

View3D is a stand-alone executable. No installation is necessary.

Building the Program

The program is written in portable C, and thus should compile on most systems with a C compiler. No features from newer C standards are used. Makefiles for GCC and the Visual Studio compiler are included, and for those of you that desire a more painful experience CMake is now supported. Presently, most development work is done on Windows with the MinGW (32 bit) compilers. To build the program

1. Download it and unpack it
2. Build the program:
   • Makefiles: Open a command prompt or terminal window, change directories to where you put the source, and run
     • make to compile with GCC
     • nmake /F Makefile.windows to compile with the Visual Studio compiler
   • CMake: Create a build directory, point CMake at it and the source directory and then do the usual thing. This will build the program and the documentation (using the UseLatex CMake macros: www.github.com/kmorel/UseLATEX). This is relatively new and may not really work all that well yet.

That's it. Standard caveats with respect to paths apply.

Running the Program

The program is run from the command line:

View3D inputfile.vs3 outputfile

This will produce an two files in the current directory: outputfile and View3D.log.

-- Jason DeGraw

April 29, 2014

view3d's Issues

View Factor from Points

Hey,

Is it possible to calculate the view factor from a point to a given set of surfaces?
I can't find anything about it in the documentation, but I seem to recall it been described in the original paper.

Cheers!
Christian

64 bit versions give incorrect results

Executables compiled with 64 bit versions of the MinGW compilers will run but sometimes produce bad output, including for the Pinney and Bean (test 4) L-shaped room case. It is not clear what triggers the issue, but it appears to be related to obstructions, subsurfaces, or combination of surfaces.

Compilation fails using VS2012

I followed the posted directions to run the make file in the VS2012 command prompt, but the compilation failed. I was left with several unresolved external symbol errors, as shown in the image:

Any ideas?

View3D Auxiliary Programs

The README describes how to run the View3D VS3file VFfile programs, but none of the other auxiliary programs.

For example, ViewGr, ViewEm, ViewHT, VS3fix, VFbintxt. See the attached document detailing the purposes of the additional auxiliary programs.

UsingView3D.pdf

Can we readily provide support for these function calls?

VDOT, VDOTW, VCROSS functions

The functions VDOT, VDOTW, VCROSS appear in View3D. The purpose of these functions seems clear enough, they are not defined in the View3D source. Perhaps they are defined as part of a standard library?

Can anyone tell me where these functions are defined?

Thanks.