topo-vol is a topology guided volume exploration and analysis tool, written for the final project in Bei Wang's Computational Topology Course. It is built on top of the Topology ToolKit and VTK for computation, and uses ImGui and a custom rendering system for the UI and volume rendering. By computing relevant topological structures (e.g. the contour tree) and classifying segments of data corresponding to the branches in this tree we can avoid occlusion issues with global transfer functions and create more useful, detailed renderings. See the report for more details.
In addition to VTK and TTK you'll need GLM and SDL2, these are likely available through your system's package manager if you're on Linux. We've only tested the program so far on Linux, however if you can build TTK on Windows or OS X you can likely build and run our program. OpenGL 4.3 is also required.
After getting GLM and SDL2 download and build VTK and follow the
TTK installation instructions to build TTK.
Compiling TTK is optional, due to how they configure their build system when using it externally
the required TTK code is actually built by topo-vol when you build the project.
Once these packages are setup topo-vol can be built with CMake. When running CMake you'll
want to specify the location of the VTK cmake file if it's non-standard, and the path to ttk.cmake
in TTK's core/ directory. For example:
Note: I've fixed TTK's build system for compiling it as a library, use my fork and make and install TTK until this is merged into main TTK. (It will be merged soon).
cmake -DVTK_DIR=<path to VTKConfig.cmake> \
-DTTKBase_DIR=<path to TTKBaseConfig.cmake> \
-DTTKVTK_DIR=<path to TTKVTKConfig.cmake>
If you're using the main repo of TTK, note that due to some issues with how TTK
handles compiling packages depending on it
as a library, our cmake will copy a modified ttk.cmake over the one in TTK's directory which will essentially
build TTK into .lib files and accelerate compilation.
After this you should be able to run make -j8 to build the program and make install to copy
the shaders where the executable will look for them in the build directory. We recommend
building the Release build for better performance.
topo-vol currently supports scalar-field VTI files with data type char, unsigned char,
short, unsigned short or float.
To get some data to test on you can load some of the raw files from the
Open SciVis Datasets
collection directly, or load them in ParaView and export them as VTI. If you
built TTK with ParaView you can use that build to convert the data. Note that larger datasets
will require much longer computation time and memory. When loading a raw file the
file name must contain information about the dimensions and data type, in the format
used by the Open SciVis Datasets collection. The format is:
<volume name>_<X dim>x<Y dim>x<Z dim>_<data type>.raw
Here's an example screenshot after performing separate classification of different segments in the contour tree on the Nucleon dataset. For an example of using the system for analysis see the video of a Tooth analysis session.
