Software Execution
This section describes the data the user must supply to successfully execute
GridEx. The valid data formats and their associated geometry kernels
are explained in detail below.
Required
Data
GridEx
operates upon geometry in the form of a solid model which defines the
computational boundary for the body of interest. It is generally
assumed that this model has been developed using a third party CAD
package using the full capability afforded therein to efficiently
produce a manifold or "water tight" solid model of the geometry. Such
models may be available from earlier phases of the design
process. Additionally, the ability to create geometric
primitives, utilizing the original CAD system kernel, is available within
GridEx. Boolean combinations of geometry are provided
thereby allowing the user to define the computational domain
of interest.
Through the use of CAPrI,
a third-party CAD-vendor neutral Application Programming Interface (API) from MIT, GridEx is able to support the use of the following
popular CAD packages:
-
CATIA,
by Dassault Systems.
With CAPRI, GridEx
can efficiently "communicate"
directly with the appropriate geometry kernel thus ensuring that all meshing
and geometry operations performed within the software are fully and seamlessly
linked to the underlying geometry as all such operations make use
of the native definitions contained
within the model file.
GridEx is thus essentially immune
to modeling issues which typically arise due a translation of native CAD
data into IGES or STEP formats. This functionality, however, requires an
active license of the respective CAD package as its geometry kernel is
accessed directly by the software. It also requires that the input
geometry be in the form of a proper manifold as defined by the native CAD
geometry kernel (i.e., a valid solid).
Though it is
not the preferred mode of operation, GridEx will also accept a solid
model description in a native format to accommodate situations
in which the GridTool
software has been used to develop the model. In any event, the model
must be complete and possess no geometric faults which violate the manifold
requirement as GridEx offers no facilities with which to repair
such deficiencies or modify configuration geometry. With a valid
solid model, the user is ready to begin processing within GridEx.
Software
Execution
GridEx
execution requires, at a minimum, the command line identification of the
solid modeling kernel. The command has the form:
where kernel
may be specified as either:
-
Ideas,
-
Parasolid,
-
Pro-E,
-
Catia, or
-
Native
and
is case insensitive. Specification of other than the Native "kernel"
will instruct GridEx to link the designated geometry kernel.
Specific model
file name extensions are dictated by the respective modeling kernel and
are required as listed in the table below:
|
Model file
|
Default extension
|
|
I-DEAS
|
*.mf1,*.mf2
|
|
Parasolid
|
*.xmt_txt
|
|
Pro-E
|
*.prt.#
|
|
Catia
|
*.model
|
The
Native
option is provided for situations as described above where legacy GridTool
data is available. No external geometry kernel is linked for this selection.
The command described above can optionally be appended with options
if it is desired that the model file be read from the command line. The valid
options
consist of the following:
-capri,
-fbg,
-vbg,
-P, or
-M
The
capri option instructs GridEx to read the designated model file
(having the extension required by the respective kernel), thus the command becomes
GridEx kernel -capri modelfile.extension
However, if a CAPrI ancillary data
file (modelfile.capri) exists, it will be loaded first and subsequently
trigger the loading of the model file. This ancillary file exists if the model
has been previously processed within GridEx or CAPrI and
output as CAPrI geometry. This ancillary file supplements the kernel
model file with additional data (including Boundaries, Tags, etc.) but contains no
actual geometry definition.
The fbg option indicates a FELISA background mesh
file (modelfile.bac) containing information relating to the definition
of the background grid with
all associated sources.
The vbg option indicates a VGRID background mesh to be read from a
traditional VGRID D3M file (modelfile.d3m). Only the background grid
sources are read from the D3M file. All other information
(curves, patches, etc.) is discarded.
The
P option indicates an I-DEAS project file [Project].
The
M option indicates an I-DEAS model file [ModelFile].
Alternatively,
the importing of model data can be performed using the
File
Dialog facilities provided within the software.
|
