cdwrite#

Mapdl.cdwrite(option='', fname='', ext='', fnamei='', exti='', fmat='', **kwargs)#

Writes geometry and load database items to a file.

APDL Command: CDWRITE

Parameters:

option

Selects which data to write:

ALL: Write all appropriate geometry, material property, load, and component data (default). Two files will be produced. Fname.Ext will contain all data items mentioned in “Notes”, except the solid model data. Fnamei.Exti will contain the solid model geometry and solid model loads data in the form of IGES commands. This option is not valid when CDOPT,ANF is active.
COMB: Write all data mentioned, but to a single file, Fname.Ext. Solid model geometry data will be written in either IGES or ANF format as specified in the CDOPT command, followed by the remainder of the data in the form of ANSYS commands. More information on these (IGES/ANF) file formats is provided in “Notes”.
DB: Write all database information except the solid model and solid model loads to Fname.Ext in the form of ANSYS commands. This option is not valid when CDOPT,ANF is active.
SOLID: Write only the solid model geometry and solid model load data. This output will be in IGES or ANF format, as specified in the CDOPT command. More information on these (IGES/ANF) file formats is provided in “Notes”.
GEOM: Write only element and nodal geometry data. Neither solid model geometry nor element attribute data will be written. One file, Fname.Ext, will be produced. Use CDREAD,DB to read in a file written with this option. Element types [ET] compatible with the connectivity of the elements on the file must first be defined before reading the file in with CDREAD,DB.
CM: Write only node and element component and geometry data to Fname.Ext.
MAT: Write only material property data (both linear and nonlinear) to Fname.Ext.
LOAD: Write only loads for current load step to Fname.Ext.
SECT: Write only section data to Fname.Ext. Pretension sections are not included.

fname

File name and directory path (248 characters maximum, including the characters needed for the directory path). An unspecified directory path defaults to the working directory; in this case, you can use all 248 characters for the file name.

ext

Filename extension (eight-character maximum).

fnamei

Name of the IGES file and its directory path (248 characters maximum, including directory). If you do not specify a directory path, it will default to your working directory and you can use all 248 characters for the file name.

exti

Filename extension (eight-character maximum).

fmat

Format of the output file (defaults to BLOCKED).

BLOCKED: Blocked format. This format allows faster reading of the output file. The time savings is most significant when BLOCKED is used to read .cdb files associated with very large models.
UNBLOCKED: Unblocked format.

Returns:

str: Mapdl command output.

Notes

Load data includes the current load step only. Loads applied to the solid model (if any) are automatically transferred to the finite element model when this command is issued. CDWRITE writes out solid model loads for meshed models only. If the model is not meshed, the solid model loads cannot be saved. Component data include component definitions, but not assembly definitions. Appropriate NUMOFF commands are included at the beginning of the file; this is to avoid overlap of an existing database when the file is read in.

Element order information (resulting from a WAVES command) is not written. The data in the database remain untouched.

Solution control commands are typically not written to the file unless you specifically change a default solution setting.

CDWRITE does not support the GSBDATA and GSGDATA commands, and these commands are not written to the file.

The data may be reread (on a different machine, for example) with the CDREAD command. Caution: When the file is read in, the NUMOFF,MAT command may cause a mismatch between material definitions and material numbers referenced by certain loads and element real constants. See NUMOFF for details. Also, be aware that the files created by the CDWRITE command explicitly set the active coordinate system to Cartesian (CSYS,0).

You should generally use the blocked format (Fmat = BLOCKED) when writing out model data with CDWRITE. This is a compressed data format that greatly reduces the time required to read large models through the CDREAD command. The blocked and unblocked formats are described in Chapter 3 of the Guide to Interfacing with ANSYS.

If you use CDWRITE in any of the derived products (ANSYS Emag, ANSYS Professional), then before reading the file, you must edit the Jobname.cdb file to remove commands that are not available in the respective component product.

The CDWRITE command writes PART information for any ANSYS LS-DYNA input file to the Jobname.cdb file via the EDPREAD command. (EDPREAD is not a documented command; it is written only when the CDWRITE command is issued.) The PART information can be automatically read in via the CDREAD command; however, if more than one Jobname.cdb file is read, the PART list from the last Jobname.cdb file overwrites the existing PART list of the total model. This behavior affects all PART-related commands contained in the Jobname.cdb file. You can join models, but not PART-related inputs, which you must modify using the newly-created PART numbers. In limited cases, an update of the PART list (EDWRITE,PUPDATE) is possible; doing so requires that no used combination of MAT/TYPE/REAL appears more than once in the list.

The CDWRITE command does not support (for beam meshing) any line operation that relies on solid model associativity. For example, meshing the areas adjacent to the meshed line, plotting the line that contains the orientation nodes, or clearing the mesh from the line that contains orientation nodes may not work as expected. For more information about beam meshing, see Meshing Your Solid Model in the Modeling and Meshing Guide.

IGES and ANF File Formats for Solid Model Geometry Information

The format used for solid model geometry information is determined by the current CDOPT command setting. The default format is IGES.

IGES option (default) to write solid model information (CDOPT, IGS):

Before writing solid model entities, select all corresponding lower level entities (ALLSEL,BELOW,ALL).

Examples

Create a basic block and save it to disk.

>>> mapdl.prep7()
>>> mapdl.block(0, 1, 0, 1, 0, 1)
>>> mapdl.et(1, 186)
>>> mapdl.esize(0.25)
>>> mapdl.vmesh('ALL')
>>> mapdl.cdwrite('DB', '/tmp/mesh.cdb')
 TITLE =
 NUMBER OF ELEMENT TYPES =      1
        64 ELEMENTS CURRENTLY SELECTED.  MAX ELEMENT NUMBER =   64
       425 NODES CURRENTLY SELECTED.     MAX NODE NUMBER =     425
         8 KEYPOINTS CURRENTLY SELECTED. MAX KEYPOINT NUMBER =   8
        12 LINES CURRENTLY SELECTED.     MAX LINE NUMBER =      12
         6 AREAS CURRENTLY SELECTED.     MAX AREA NUMBER =       6
         1 VOLUMES CURRENTLY SELECTED.   MAX VOL. NUMBER =       1
 WRITE ANSYS DATABASE AS AN ANSYS INPUT FILE: /tmp/mesh.cdb

Optionally load the mesh into Python using the archive reader.

>>> from ansys.mapdl import reader as pymapdl_reader
>>> mesh = pymapdl_reader.Archive('/tmp/mesh.cdb')
>>> mesh
ANSYS Archive File mesh.cdb
 Number of Nodes:              425
 Number of Elements:           64
 Number of Element Types:      1
 Number of Node Components:    0
 Number of Element Components: 0