SDO_TIN_PKG.CREATE_MESHES

Format

SDO_TIN_PKG.CREATE_MESHES(
     base_table           IN  VARCHAR2,
     data_table           IN  VARCHAR2,
     tin_id               IN  NUMBER,
     tin_tol              IN  NUMBER,
     blk_size             IN  NUMBER DEFAULT NULL,
     inptab               IN  VARCHAR2,
     srid                 IN  NUMBER,
     feature_size         IN  NUMBER,
     max_angle            IN  NUMBER DEFAULT 90.0,
     blocking             IN  VARCHAR2 DEFAULT 'Consecutive-Mesh-Based',
     batch_size_pts       IN  NUMBER DEFAULT 100000
     );

Description

Generates a 3D mesh from a set of three-dimensional points.

Parameters

base_table

Name of the destination object table containing the new MDSYS.SDO_TIN object.

data_table

Name of the destination data table containing the mesh blocks.

tin_id

ID value of the new mesh.

tin_tol

Tolerance value for the resulting mesh of type SDO_TIN.

blk_size

(Not currently used.)

inptab

Name of the table containing the input point data with numeric columns VAL_Di for x, y, and z.

srid

The coordinate reference system of the point data.

feature_size

The size of the kind of feature that should remain recognizable in the mesh resolution. Small feature size implies more details. But it also means that there would be more voids in the mesh, if the point distribution is not dense enough.

max_angle

The maximum admissible angle (in degrees) between neighboring triangles.

blocking

Currently, the only supported option is ‘Consecutive-Mesh-Based’.

batch_size_pts

The batch size of points read, internally, while generating the mesh.

Usage Notes

The procedure SDO_TIN_PKG.CREATE_MESHES can be used to generate a 3D mesh from the points specified in the inptab parameter. This 3D mesh computation is similar to the computation of a TIN. But unlike TINs which represent only 2 1/2 D surfaces, a mesh can much more represent 3D structures, including closed volumes.

The max_angle parameter specifies the maximum cutoff angle, when generating consecutive meshes. Two parallel triangles have angle zero, unless they have opposing normals (right-handed rule), in which case they have angle 180 degrees. A surface facing up has opposing normal with a surface facing down. In a mesh, the surface normal should face outside from a solid.

The output of the mesh processing is stored as a new SDO_TIN object in the destination tables specified by base_table and data_table parameters.

See 3D Mesh Modeling for more concepts.

Examples

The following example generates a 3D mesh as shown:

SQL> call
  2    sdo_tin_pkg.create_meshes(
  3      base_table   => 'MESHES',
  4      data_table   => 'BLOCKS',
  5      tin_id       => 3,
  6      tin_tol      => 0.05,
  7      blk_size     => null,
  8      inptab       => 'INPTAB3',
  9      srid         => 27700,
 10      feature_size => 2,
 11      max_angle    => 120);