Difference between revisions of "ImprovingMeshQualityOfMarchingCubes"

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== The paper ==
[[Image:Macet_paper_teaser.png]]


Carlos Dietrich, Joao Comba, Luciana Nedel, Carlos Scheidegger, John Schreiner, Claudio Silva. Edge Transformations for Improving Mesh Quality of Marching Cubes. 2007, submitted.
Carlos Dietrich, Joao Comba, Luciana Nedel, Carlos Scheidegger, John Schreiner, Claudio Silva. Edge Transformations for Improving Mesh Quality of Marching Cubes. 2007, submitted.


== Reproducing the results ==
=== Abstract ===


The results in this paper can be completely reproduced using open-source software and publicly available datasets. We will soon post here the set of workflows needed to run the experiments directly in VisTrails, along with the necessary software.
Marching Cubes is a popular choice for isosurface
extraction from regular grids due to its simplicity, robustness, and
efficiency.  One of the key shortcomings of this approach is the
quality of the resulting meshes, which tend to have many poorly
shaped and degenerate triangles.
This issue is often addressed
through post processing operations such as smoothing.  As we
describe, while these improve the mesh, they do not remove all
degeneracies, and incur an increased and unbounded error between the
resulting mesh and the  original isosurface. 
Rather than modifying the resulting mesh, we propose a method
to modify the grid on which Marching Cubes operates.
This modification greatly increases the quality of the extracted
isosurface. In our experiments, it did not create a single
degenerate triangle, unlike any other method we experimented with.
Our method essentially eliminates postprocessing related to mesh
quality. We show improvements in subsequent mesh processing,
using the generated surface directly as input to a tetrahedral mesh
generator.
The method incurs minimal computational overhead,
requiring at most twice the execution time of the original Marching
Cubes algorithm in our experiments. Most importantly, it can be
readily integrated in existing Marching Cubes implementations, and is
orthogonal to many Marching Cubes enhancements (such as out-of-core
and acceleration methods). The method can also be directly applied
to other related isosurface extraction algorithms such as Marching
Tetrahedra, and Marching Octahedra.


== Alternative #1: Ubuntu repository ==
== Get the software ==


If you run Ubuntu Linux, you can simply add our APT repository
To compile the basic software, which generates isosurfaces using Macet, you will need [http://teem.sourceforge.net teem] and [http://www.boost.org boost] to be installed. There is a linux makefile and a Visual Studio solution file available. The source is available [http://www.sci.utah.edu/~cscheid/software/macet.tar.gz here (.tar.gz)] or [http://www.sci.utah.edu/~cscheid/software/macet.zip here (.zip)]


deb http://vgc.sci.utah.edu/ubuntu edgy main
== Usage ==


and install the package "ectmc" we are currently creating. This will install all the software you need with the right versions, so running the experiments will be a matter of downloading the actual vistrail containing the workflows and running it:
To generate a macet isosurface:


  # apt-get install ectmc
  ./macet <nrrd_file> <iso_value> <output_off_file> -isCombined


Follow [[InstallingVisTrailsOnUbuntu | these instructions]].
To generate a regular Marching Cubes isosurface:


== Alternative #2: Downloading and using VisTrails manually ==
./macet <nrrd_file> <iso_value> <output_off_file>
 
You can download all the individual software manually.
 
=== Our algorithm ===
 
[http://www.sci.utah.edu/~cscheid/software/ectmc/ectmc.zip ZIP File]
 
[http://www.sci.utah.edu/~cscheid/software/ectmc/ectmc.tar.gz Gzipped tarball]
 
==== Core requirements ====
 
[http://teem.sourceforge.net/ Teem]
 
[http://www.cs.princeton.edu/gfx/proj/trimesh2/ Trimesh2]
 
[http://www.boost.org/ Boost]
 
[http://vcg.sourceforge.net/tiki-index.php?page=Metro Metro]
 
[http://tetgen.berlios.de/ Tetgen]
 
=== Requirements for running the experiments ===
 
* [http://www.vtk.org VTK] Version 5.0 or higher, with Python bindings
* [http://matplotlib.sourceforge.net] Matplotlib
* [http://afront.sourceforge.net] Afront
 
=== VisTrails packages ===
 
(TODO: Finish the text) [http://www.sci.utah.edu/~cscheid/software/ectmc/macet_packages.tar.gz tarball of all necessary VisTrails packages.]
 
== Datasets ==
 
The datasets we used are all available on the [http://www.volvis.org Volvis website]. We use the NRRD toolset to access the data, so you need the NRRD header files to go with the raw volumes. You can get the NRRD headers and dataset we used [http://www.sci.utah.edu/~cscheid/software/ectmc/data here].
 
== Vistrail ==
 
The vistrail you will need to open is available [http://www.sci.utah.edu/~cscheid/software/ectmc/macet.xml here]. Each version shows a different technique. The topmost one is the one we are proposing (MACET).

Latest revision as of 20:39, 21 June 2007

Macet paper teaser.png

Carlos Dietrich, Joao Comba, Luciana Nedel, Carlos Scheidegger, John Schreiner, Claudio Silva. Edge Transformations for Improving Mesh Quality of Marching Cubes. 2007, submitted.

Abstract

Marching Cubes is a popular choice for isosurface extraction from regular grids due to its simplicity, robustness, and efficiency. One of the key shortcomings of this approach is the quality of the resulting meshes, which tend to have many poorly shaped and degenerate triangles. This issue is often addressed through post processing operations such as smoothing. As we describe, while these improve the mesh, they do not remove all degeneracies, and incur an increased and unbounded error between the resulting mesh and the original isosurface. Rather than modifying the resulting mesh, we propose a method to modify the grid on which Marching Cubes operates. This modification greatly increases the quality of the extracted isosurface. In our experiments, it did not create a single degenerate triangle, unlike any other method we experimented with. Our method essentially eliminates postprocessing related to mesh quality. We show improvements in subsequent mesh processing, using the generated surface directly as input to a tetrahedral mesh generator. The method incurs minimal computational overhead, requiring at most twice the execution time of the original Marching Cubes algorithm in our experiments. Most importantly, it can be readily integrated in existing Marching Cubes implementations, and is orthogonal to many Marching Cubes enhancements (such as out-of-core and acceleration methods). The method can also be directly applied to other related isosurface extraction algorithms such as Marching Tetrahedra, and Marching Octahedra.

Get the software

To compile the basic software, which generates isosurfaces using Macet, you will need teem and boost to be installed. There is a linux makefile and a Visual Studio solution file available. The source is available here (.tar.gz) or here (.zip)

Usage

To generate a macet isosurface:

./macet <nrrd_file> <iso_value> <output_off_file> -isCombined

To generate a regular Marching Cubes isosurface:

./macet <nrrd_file> <iso_value> <output_off_file>