SmallUPBP is a small physically based renderer that implements the unified points, beams and paths algorithm described in the paper
Unifying points, beams, and paths in volumetric light transport simulation
Jaroslav Křivánek, Iliyan Georgiev, Toshiya Hachisuka, Petr Vévoda, Martin Šik, Derek Nowrouzezahrai, and Wojciech Jarosz
ACM Transactions on Graphics 33(4) (SIGGRAPH 2014)
as well as a number of other algorithms, notably including progressive photon mapping, (progressive) bidirectional photon mapping, bidirectional path tracing, vertex connection and merging, beam radiance estimate, and photon beams.
The code compiles to a command line program that can render images of a number of predefined scenes using the provided algorithms as well as of custom scenes supplied by a user.
It is based on the SmallVCM renderer developed in 2012 by Tomáš Davidovič and Iliyan Georgiev. SmallUPBP heavily modifies it to add support for participating media, point and beam-based volumetric estimators, and loading scenes in OBJ. Its main authors are Petr Vévoda, Martin Šik and Jaroslav Křivánek.
SmallUPBP is released under the following license:
- MIT license - most of the supplied code, scenes and associated files
- Apache 2.0 license - Embree
- modified BSD licence - OpenEXR
This code was used to render the images in the aforementioned paper and all scenes
and batch files necessary for reproducing the presented results are provided (see the
It is released for educational and research purposes and neither the code nor
its documentation claims to be complete and bug-free. We apologize for any errors
Thorough description of the renderer, including its usage and implementation details as well as its theoretical background, is given by Petr Vévoda in his thesis
Robust light transport simulation in participating media
Master's thesis. Charles University in Prague, Prague, Czech Republic, February 2015.
Here we present its slightly modified version with minor fixes and improvements. Note that the thesis originally refers to a DVD. Content of the DVD is almost the same as of the archive you can download from this page.
The archive you can download from this page contains following folders and files:
- embree-2.0 - source code of Embree
- OpenEXR - header files and source code of OpenEXR
- scenes - scene and batch files used to render images in the UPBP paper
- SmallUPBP - source code of this renderer
- Tools - a few scripts for displaying and comparing rendered images
- README.txt - this text
The source code is divided into two Microsoft Visual Studio 2013 solutions. The first one,
OpenEXR.sln in the
OpenEXR\src folder, contains single project
of the same name with the OpenEXR library. The second one,
SmallUPBP folder, contains three projects: embree, sys
and SmallUPBP. The first two are parts of Embree and need to be compiled
with the OpenEXR project as static libraries and linked with the main SmallUPBP project.
The easiest way to do this is to use the provided solutions. Firstly, build the
solution. It creates the static library
depending on the selected configuration) in the
OpenEXR folder. Then build
It creates the remaining
sys.lib static libraries
as well as the executable
SmallUPBP.exe file in the
(or in the
Build\SmallUPBP\x64\Debug folder depending on the selected configuration).
Note that the build configurations of both solutions must match. The
file is completely independent of any other files and can be moved and run freely
(however, the batch files in the
scenes folder expect it in the original location).
As mentioned earlier, the resulting executable file is a command line program.
SmallUPBP.exe -h or
SmallUPBP.exe -hf to see a short and full help respectively.
The short help contains only basic arguments sufficient to render your first images
while the full version lists all arguments the program knows. For more information
about the program please see the Petr Vévoda's thesis.