31.2 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
forx
,y
, andz
. - 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 ½ 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);
Parent topic: SDO_TIN_PKG Package (TINs)