This repository contains programs for the study and understanding of bounding volume hierarchy construction (BVH) around high-valence mesh features. The Mesh Oriented DataBase MOAB is used to do so.
This study centers around the construction of a high-valence test model. This model begins as the surface faceting of a cube (2 triangles per face). The faceting of one face is then deleted and replaced with a manually generated high-valence region which can be altered in size based on the fractional area of the cube face. The valence of the region can also be controlled.
Several programs exist in this repository to examine MOAB's bounding volume hierarchy construction around the high-valence test model and in some cases other models as well.
Generates a high valence test model with area fraction,
./hv_cube <A_f> <v_n>
Sweeps the area fraction and/or valence of the high-valence model from 0 to the specified value. It will then fire 600k randomly oriented rays using the BVH into the high valence surface of the cube and time the result. It will then write this information for each model generated to a file called "data.dat".
./sweep <A_f> <v_n>
The number of intervals used to approach the specified area fraction and valence
are input using the options --af_ints and --v_ints, respectively.
A specific parameter of MOAB's BVH hierarchy constructor can also be swept if
desired. The wosrt splitting ratio (wsr) can be set and iterated for all area
fractions and valencies by setting the --min_wsr, --max_wsr, and
--wsr_ints options.
This program will load a MOAB model into a DAGMC instance, generate the BVH, and then write the BVH into a .vtk database for visualization puroposes. Each file in the vtk databse represents all of the boxes for a given level in the BVH.
./write_obbs <filename>
If desired, the triangles of any leaf nodes can be written along with their .vtk
file for more information using the --with-tris option. A nice demonstration
of visualzation using the resulting .vtk database can be seen here.
This program counts the number of leaf nodes in the BVH for a given model. It also provides some information about the average number of leaves in a model's BVH.
./count_leaves <filename>
This is a nice way to ensure that a well-formed BVH is being created for the file.
This program is designed to fire a single ray through the OBB tree of a volume in the model (indicated in the command line by its GLOBAL_ID). The ray data is provided via the command line arguments below.
./traverse_ray <x> <y> <z> <u> <v> <w> <vol_id> <filename>
Upon successful completion, it will produce a .vtk file containing the ray that was specified (also in the command line) and all of the oriented boxes encountered upon traversal of the tree for visualization.
With a MOAB installation in the LD_LIBRARY_PATH variable, run the following in a build directory of choice:
cmake .. -DCMAKE_INSTALL_PREFIX=<install_location>