Interface Reconstruction with Directional Walking
Abstract
Young's interface reconstruction with threedimensional arbitrary mesh, in general, is rather tedious to implement compared to the case of a regular mesh. The main difficulty comes from the construction of a planar facet that bounds a certain volume inside a cell. Unlike the five basic configurations with a Cartesian mesh, there can be a great number of different configurations in the case of a general mesh. We represent a simple method that can derive the topology/geometry of the intersection of arbitrary planar objects in a uniform way. The method is based on a directional walking on the surface of objects, and links the intersection points with the paths of the walking naturally defining the intersection of objects. The method works in both two and three dimensions. The method does not take advantage of convexity, thus decomposition of an object is not necessary. Therefore, the solution with this method will have a reduced number of edges and less data storage, compared with methods that use shape decomposition. The treatment is general for arbitrary polyhedrons, and no lookup tables are needed. The same operation can easily be extended for curved geometry. The implementation of this new algorithm shall allow the interface reconstructionmore »
 Authors:
 Publication Date:
 Research Org.:
 Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
 Sponsoring Org.:
 USDOE
 OSTI Identifier:
 965953
 Report Number(s):
 LLNLPROC413323
TRN: US200921%%543
 DOE Contract Number:
 W7405ENG48
 Resource Type:
 Conference
 Resource Relation:
 Conference: Presented at: MultiMaterial Workshop, Pavia, Italy, Sep 21  Sep 25, 2009
 Country of Publication:
 United States
 Language:
 English
 Subject:
 99 GENERAL AND MISCELLANEOUS; ACCURACY; ALGORITHMS; CONSTRUCTION; DIMENSIONS; GEOMETRY; IMPLEMENTATION; SHAPE; STORAGE
Citation Formats
Yao, J. Interface Reconstruction with Directional Walking. United States: N. p., 2009.
Web.
Yao, J. Interface Reconstruction with Directional Walking. United States.
Yao, J. 2009.
"Interface Reconstruction with Directional Walking". United States.
doi:. https://www.osti.gov/servlets/purl/965953.
@article{osti_965953,
title = {Interface Reconstruction with Directional Walking},
author = {Yao, J},
abstractNote = {Young's interface reconstruction with threedimensional arbitrary mesh, in general, is rather tedious to implement compared to the case of a regular mesh. The main difficulty comes from the construction of a planar facet that bounds a certain volume inside a cell. Unlike the five basic configurations with a Cartesian mesh, there can be a great number of different configurations in the case of a general mesh. We represent a simple method that can derive the topology/geometry of the intersection of arbitrary planar objects in a uniform way. The method is based on a directional walking on the surface of objects, and links the intersection points with the paths of the walking naturally defining the intersection of objects. The method works in both two and three dimensions. The method does not take advantage of convexity, thus decomposition of an object is not necessary. Therefore, the solution with this method will have a reduced number of edges and less data storage, compared with methods that use shape decomposition. The treatment is general for arbitrary polyhedrons, and no lookup tables are needed. The same operation can easily be extended for curved geometry. The implementation of this new algorithm shall allow the interface reconstruction on an arbitrary mesh to be as simple as it is on a regular mesh. Furthermore, we exactly compute the integral of partial cell volume bounded by quadratic interface. Therefore, interface reconstruction with higher than second order accuracy can be achieved on an arbitrary mesh.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = 2009,
month = 5
}

The authors have developed an interface between the Cad system Euclid and Geant which allows to build geometries from the powerful graphical and interactive Euclid capabilities. Those geometries can be absorbed in Geant. Vice versa the geometries defined by Geant can be exported to Euclid.

Reconstruction at the Ga sub 2 Se sub 3 /GaAs epitaxial interface
A highly developed two dimensional superstructure was found at the Ga{sub 2}Se{sub 3}/GaAs epitaxial interface by transmission electron microscope observations. The atomic arrangement of the superstructure was determined by the analysis of electron diffraction patterns and high resolution transmission electron microscope images. The structure is described as a c(2 {times} 2) ordered arrangement of vacancies on the interfacial Ga plane. A possible role of the mismatch of electronic configurations at the Ga{sub 2}Se{sub 3}/GaAs interface in the formation of the vacancy ordering is discussed. 
Secondorder method for interface reconstruction in orthogonal coordinate systems
We present a method in twodimensions for reconstructing an interface from a distribution of volume fractions in a general orthogonal coordinate system. The method, in a cell by cell fashion, approximates the interface curve by a linear pro le. The approach requires only local volume fraction information for the reconstruction. An integral formulation is used that accounts for the orthogonal coordinate system in a natural way. We use nit different to approximate the slop of the required interface while retaining at worst second order accuracy for general interface orientations and an exact representation for coordinate system aligned o 
Recent work on material interface reconstruction
For the last 15 years, many Eulerian codes have relied on a series of piecewise linear interface reconstruction algorithms developed by David Youngs. In a typical Youngs` method, the material interfaces were reconstructed based upon nearly cell values of volume fractions of each material. The interfaces were locally represented by linear segments in two dimensions and by pieces of planes in three dimensions. The first step in such reconstruction was to locally approximate an interface normal. In Youngs` 3D method, a local gradient of a cellvolumefraction function was estimated and taken to be the local interface normal. A linear interfacemore »