commit 99f88d7d7f795ec7d832c26f0fc9d47658cd9888
parent b00b97104ea8e56ba54cda0e4775f6786fd361ac
Author: Vincent Eymet <vincent.eymet@meso-star.com>
Date: Mon, 15 Feb 2016 16:19:04 +0100
Rewrite the library overview of the README file
Diffstat:
| M | README.md | | | 66 | ++++++++++++++++++++++++++++++++++++++++++++++++++++-------------- |
1 file changed, 52 insertions(+), 14 deletions(-)
diff --git a/README.md b/README.md
@@ -1,26 +1,64 @@
# Star Gebhart Factor
-The purpose of this library is to numericaly solve the Gehbart factors between a
-primitive and all others primitives in a scene.
+The purpose of this C library is to numerically compute the [Gebhart
+factor](https://en.wikipedia.org/wiki/Gebhart_factor) between 3D primitives.
+The Gebhart factor *B(i,j)* between two arbitrary surfaces *i* and *j* is
+defined as the fraction of the radiative flux emitted by *i* that is absorbed
+by *j*. It is not equal to the [form
+factor](https://en.wikipedia.org/wiki/View_factor) between *i* and *j*, even
+tough the difference is subtle: the form factor is the fraction of the
+radiative flux emitted by *i*, in direction of *j* (which is not necessarily
+totally absorbed by *j*). In our case, Gebhart factors have been integrated
+over *j*, which means that we compute the fraction of the radiative flux
+emitted by *i* that is absorbed by all other surfaces. It is obviously not
+equal to one, since a fraction of the flux can be re-absorbed by *i* itself.
+
+Gebhart factors are finally used in order to compute the radiative flux
+absorbed by each surface, and subsequently the net radiative flux over each
+surface. Gebhart factors are used instead of form factors because
+of the associated flexibility in terms of reflection properties: while form
+factors are computed with the implicit assumption that surfaces are diffuse
+reflectors, there is no such restriction in the case of Gebhart factors; any
+type of reflection can be used (totally or partially specular surfaces).
+
+Star-GF estimates Gebhart factors with the Monte-Carlo method: it consists in
+simulating the trajectory of energy bundles according to a relevant physical
+model. Emission, absorption and reflection processes are therefore taken into
+account, as well as spectral aspects (surface properties can be defined as a
+function of wavelength). Should scattering processes in semi-transparent media
+be taken into consideration, it would be possible (even if actually not
+implemented). The main advantage of this statistical method is the fact it
+provides a numerical accuracy over each result: the Monte-Carlo method is often
+referred as a reference method. Also, the resulting algorithm is totally
+decoupled from the geometry: it will remain the same for every scene, no matter
+how much data is used for its description. This geometry is provided by the
+caller through a scene managed by the
+[Star-3D](https://gitlab.com/meso-star/star-gf.git) library.
## How to build
-The *Star-GF* library relies on the [CMake](http://www.cmake.org) and the
-[RCMake](https://gitlab.com/vaplv/rcmake/) package to build. It also depends on the
-[RSys](https://gitlab.com/vaplv/rsys/),
-[Star-3D](https://gitlab.com/meso-star/star-3d/),
-[Star-MC](https://gitlab.com/meso-star/star-mc/) and
+Star-GF is compatible GNU/Linux 64-bits. It relies on
+[CMake](http://www.cmake.org) and the
+[RCMake](https://gitlab.com/vaplv/rcmake/) package to build. It also depends on
+the [RSys](https://gitlab.com/vaplv/rsys/),
+[Star-3D](https://gitlab.com/meso-star/star-3d/) and
[Star-SP](https://gitlab.com/meso-star/star-sp/) libraries.
First ensure that CMake is installed on your system. Then install the RCMake
-package as well as all the *Star-GF* prerequisites. Then generate the project
-from the `cmake/CMakeLists.txt` file by appending to the `CMAKE_PREFIX_PATH`
-variable the install directories of its dependencies and the RCMake package.
+package as well as the aforementioned prerequisites. Finally generate the
+project from the `cmake/CMakeLists.txt` file by appending to the
+`CMAKE_PREFIX_PATH` variable the install directories of the previous
+dependencies. The resulting project can be edited, built, tested and installed
+as any CMake project (Refer to the [CMake
+documentation](https://cmake.org/documentation)
+for further informations on CMake).
## License
-*Star-GF* is Copyright (C) 2015 EDF S.A., France (<syrthes-support@edf.fr>). It
-is a free software released under the [OSI](http://opensource.org)-approved GPL
-v3.0 license. You are welcome to redistribute it under certain conditions;
-refer to the COPYING file for details.
+Star-GF is developed by [|Meso|Star>](www.meso-star.com) for
+Électricité De France (EDF). It is Copyright (C) 2015-2016 EDF
+S.A., France (<syrthes-support@edf.fr>). It is a free software released under
+the [OSI](http://opensource.org)-approved GPL v3.0 license. You are welcome to
+redistribute it under certain conditions; refer to the COPYING file for
+details.
