YafaRay is a free open-source raytracing engine. Raytracing  is a
rendering technique for generating realistic images by tracing the
path of light through a 3D scene.

Optional dependency: qt4. If this is installed, the Qt4 support
library for YafaRay (libyafarayqt.so) will be included in the
package. To disable Qt4 support, export QT=no in the script's
environment.