Overview

This is a repository of unstructured hexahedral meshes that were used for the experiments in the paper

Lossless Compression of Hexahedral Meshes

Peter Lindstrom and Martin Isenburg

IEEE Data Compression Conference 2008

The meshes were produced by a number of different mesh generators and were obtained from several sources. Aside from format conversion in some cases, no further processing of the meshes was done (in particular, we did not reorder vertices or hexahedra). We wish to thank the following people for sharing these meshes with us: Eric Brugger, Jeff Keasler, Ed Kokko, Marty Marinak, Scott Mitchell, Steven Owen, and Alla Sheffer.

Format

The gzipped meshes are provided in an ASCII format consisting of a list of floating-point vertex coordinates followed by a list of hexahedra referencing the vertices by their integer indices. The first line of the file is of the form # vertices hexehedra, and specifies the number of vertices and hexahedra in the file. Lines beginning with a pound sign # are otherwise treated as comments. A line of the form format GAMBIT or format CUBIT specifies how vertices are ordered within each hexahedron, as indicated by the following figure:


GAMBIT ordering	CUBIT ordering

The remainder of the file contains lines of the form v x y z that specify vertex coordinates, followed by lines h v0 v1 ... v7 that specify the vertex indices of a hexahedron. Vertex indices start at one.

Note: The meshes block and steven use C99 hexadecimal floating-point notation (e.g. numbers of the form 0x3.243f6a88p+03) to "losslessly" store double-precision floating-point numbers (these were output using the %a printf format). In C99 such numbers are read using the usual %lf scanf format for double-precision floating-point numbers. C++ compilers like GNU g++ 3.2.3 and Intel ICC 9.1 support such hexadecimal floating-point literals.

Meshes

	block (1.3 MB) Vertices: 101,401 Hexahedra: 93,750 Source: Jeff Keasler, LLNL Mesh generator: ALE3D internal Notes: Block-structured test mesh. This mesh contains nonmanifold edges.
	bump2 (45 KB) Vertices: 1,665 Hexahedra: 1,189 Source: Alla Sheffer, UBC Mesh generator: GAMBIT
	c1 (2.0 MB) Vertices: 78,618 Hexahedra: 71,572 Source: Alla Sheffer, UBC Mesh generator: GAMBIT
	cylinder (12 MB) Vertices: 500,055 Hexahedra: 482,900 Source: Ed Kokko, LLNL Mesh generator: CUBIT
	fru (160 KB) Vertices: 5,124 Hexahedra: 4,360 Source: Alla Sheffer, UBC Mesh generator: GAMBIT
	grid16 (40 KB) Vertices: 4,096 Hexahedra: 3,375 Source: Peter Lindstrom, LLNL Notes: Regular grid in natural 3D array order.
	hanger (5.2 KB) Vertices: 382 Hexahedra: 171 Source: Scott Mitchell, Sandia
	hutch (170 KB) Vertices: 8,790 Hexahedra: 8,172 Source: Scott Mitchell, Sandia
	hydra (1.9 MB) Vertices: 98,357 Hexahedra: 141,960 Source: Marty Marinak, LLNL Notes: HYDRA simulation of ICF capsule implosion. This mesh contains degenerate elements.
	mdg-1b (58 KB) Vertices: 4,510 Hexahedra: 3,710 Source: Steven Owen, Sandia
	shaft (240 KB) Vertices: 9,218 Hexahedra: 6,883 Source: Alla Sheffer, UBC Mesh generator: GAMBIT
	steven (1.9 MB) Vertices: 96,030 Hexahedra: 81,832 Source: Jeff Keasler, LLNL Mesh generator: ALE3D internal Notes: Steven Test mesh.
	test (38 KB) Vertices: 3,198 Hexahedra: 2,386 Source: Steven Owen, Sandia
	ucd3d (29 KB) Vertices: 2,646 Hexahedra: 2,000 Source: Eric Brugger, LLNL Notes: Curvilinear mesh distributed with VisIt.