MT JADE

The program jademt is a modification of jade 1.0 developed by the Visual Computing Group of the National Research Council (CNR), Pisa, Italy (see http://vcg.iei.pi.cnr.it/homepage.html).

The code has been modified under the authorization of the Visual Computing Group of the National Research Council (CNR), Pisa Italy.
The modification consists of having added calls to functions of the MT library, necessary to build a Multi-Triangulation, as well as a mechanism for guaranteeing a consistent orientation of all triangles generated at any stage of the decimation process.

We gratefully acknowledge the Visual Computing Group, CNR, Pisa, for having provided the code of Jade and authorized its modification.

The source code of Jademt is not distributed because it contains reserved parts which are property of the Visual Computing Group, CNR, Pisa.

What follows is extracted from the original USERS_MANUAL file provided with jade 1.0.

General Information

JADE's main features are :

• approximation error: an accurate estimation of the approximation error introduced in the simplification process;
• compression factor: a reduction factor comparable or better the other approaches, under the same level of approximation;
• working domain: wide generality, the algorithm manages self intersecting, not manifold, not orientable mesh;
• space/time efficency: short simplification time and low memory consumption, to allow the management of large meshes.

How to run the program

Jademt [Options] InFile OutFile

Avaliable options

• -h Show an help message
• -p(value) Set distance to Error threshold to "value"% of bounding box.
  With this option the simplification will be executed with with a global bound of "value"%. (ex. -p1 execute a reduction with global error bound of 1%).
• -d(value) Set the percentage decimation algorithm. "value"% of vertices will be removed form the mesh.
  With this option Jade will use the output number of vertices as exit condition (ex. -d90 execute a 10:1 reduction of the input mesh). Errors are always calculated as percentage of bounding box diagonal.
  Remark: Options -p and -d are mutually exclusive, the -d option has precedence over the -p option.
• -e(angle) Set Internal Edge threshold to ANGLE (degree).
  This option set the angle over that a vertex is classified as an INTERNAL EDGE or INTERNAL CORNER (see paper for an explanation of vertex classification).
• -r Do not remove BOUNDARY vertices.
  This option preserves all BOUNDARY vertices of the input mesh.
• -f(value) Use FLIPPING enhance routine:
  • 0: No flipping.
  • 1: Volume flipping (FAST).
  • 2: Patch Distance flipping (BEST).
  The flipping algorithm is the CORE technique of JADE. Use -f1 for fast approximation or -f2 for best reduction.
• -q(value) Set triangle quality threshold;
  This parameter is used to control output triangle quality; it is in the 0-1 interval (greater is better). Good values from 0.1 to 0.25, default 0.1.
  If "value" is too high the speed of the algorithm will decrease and reduction percentage became poor. On the other hand, if it is too low the output mesh can contain poor quality triangles.

Where to find the results

The triangles of the Multi-Triangulation are consistently oriented through the surface, but in some cases the orientation is not consistent with the semantics of the data (e.g., the bounding surface of a solid object may be oriented in such a way that the front side is the one inside the object.
An MT can be reversed by using the program reverse provided in the utilities. Remember to reverse the MT before computing its vertex normals.

Mesh Formats

• the MSH format, a plain binary RAW format;
• the IMSH format, an indexed binary format.

X1,Y1,Z1,          // First vertex
X2,Y2,Z2,          // Second vertex   -->   First Triangle
X3,Y3,Z3,          // Third vertex
...
Xk,Yk,Yk,          // First vertex
Xk+1,Yk+1,Zk+1,    // Second vertex   -->   Last Triangle
Xk+2,Yk+2,Zk+2     // Third vertex

The IMSH format contains some additional information an uses half the space of MSH format listed above. Structure example (IMSH format):

"INDEXED"     // Tag of 7 bytes with the word indexed (all capital letters)
NumVertices   // Number of Vertices in this mesh (INTEGER)

X1,Y1,Z1      // Coordinates of the first vertex (FLOATs)
...
Xn,Yn,Zn      // Coordinates of the last vertex (FLOATs) n = NumVertices

NumTriangles  // Number of Triangles in this mesh (INTEGER)
v1,v2,v3      // Index of vertices used by the first triangle (INTEGERs)
...
vk,vk+1,vk+2  // Index of vertices used by the last triangle (INTEGERs)

Conversion tool

-----------------------------------------------------------------------
|               From                |               To                |
-----------------------------------------------------------------------
|   Mesh Optimization *.M format    |              IMSH               |
|               IMSH                |   Mesh Optimization *.M format  |
|             CyberWare             |               MSH               |
|            VTK PolyData           |              IMSH               |
|               IMSH                |          VTK PolyData           |
|               HIS                 |              IMSH               |
|               IMSH                |               MSH               |
|               HIS                 |               WRL               |
|            ASCII PLY              |              IMSH               |
|               IMSH                |            ASCII PLY            |
-----------------------------------------------------------------------

Conversion Parameters

• -? Show help message
• -a(Value) Scale mesh coordinate by Value
• -o Convert from Hoppe (.m format) to indexed MSH
• -s Convert from indexed MSH to Hoppe (.m format)
• -c Convert from Cyber to MSH (Incomplete, handle only a CyberWare subformat)
• -v Convert from VTK (only DATASET POLYDATA) to indexed MSH
• -z Convert from indexed MSH to VTK (DATASET POLYDATA)
• -t(Value) Extract from HIS a MSH with Value error bound
• -k Convert from indexed MSH to MSH
• -h Convert from HIS to WRL
• -m Convert from MSH to ASCII PLY