GiD - The personal pre and post processor

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Menu: Files->Import→STEP...


With this option it is possible to read a CAD file in STEP standard format (AP214 Automotive Application protocol)


DXF


Menu: Files->Import->DXF...
With this option it is possible to read a file in DXF format (AutoCAD exchange format).
GiD is able to read most of the entities, which are: POINT, LINE, ARC, CIRCLE, ELLIPSE, SPLINE, LWPOLYLINE, MLINE, POLYLINE, VERTEX, TRACE, SOLID, 3DFACE, 3DSOLID, BLOCK, INSERT
A very important parameter to consider is how the points must be joined. This means that points that are close to each other must be converted to a single point. This is done by defining the variable ImportTolerance (see Preferences ). Points closer together than ImportTolerance will be considered as a single point. Straight lines that share both points are also converted to a single line.
You can use the Collapse function (see Collapse ) to join more entities.


Parasolid


Menu: Files->Import->Parasolid...
With this option it is possible to read a file in the Parasolid format (untile version 30000 - ASCII or binary).
The most usual Parasolid file extension is .x_t for ASCII and .x_b for binary format.
The variable ImportTolerance (see Preferences ) controls the creation of new points when a Parasolid file is read. Points are therefore defined as unique if they lie further away than this tolerance distance from another already defined point. Curves are considered identical if they have the same points at their extremes and the "mean proportional distance" between them is smaller than the tolerance. Surfaces can also be collapsed.

ACIS


Menu: Files->Import->ACIS...
With this option it is possible to read a file in ACIS format (version 2000). GiD reads the ASCII version with the SAT Save File Format. ACIS files (in ASCII) have the .sat extension.

VDA


Menu: Files->Import->VDA...
With this option it is possible to read a file in VDA 2.0 format.
A very important parameter to consider is how the points must be joined. This means that points that are close to each other must be converted to a single point. This is done by defining the variable ImportTolerance (see Preferences ). Points closer together than ImportTolerance will be considered as a single point. Straight lines that share both points are also converted to a single line.
The Collapse function (see Collapse ) can be used to join more entities.

Rhinoceros


Menu: Files->Import->Rhinoceros...
With this option it is possible to read Rhinoceros 5.0 CAD files. This files have the .3dm extension.

Shapefile


Menu: Files->Import->Shapefile...
With this option it is possible to read a GIS file written in ESRI Shapefile format (version 1000). Shapefiles have the .shp extension.

XYZ points


Menu: Files->Import->XYZ points...
With this option it is possible to read a set of geometric points. This format is ASCII and consists the coordinates of the points separated with spaces.
Note: If only 2 coordinates are specified, z=0 is assumed.
If 'Automatic collapse after import' was set, after the import near points will be joined, The variable ImportTolerance (see Preferences ) controls the joining distance.
The file browser allow some extra "Import options". Usually these options are hidden, press the arrow icon to show them
Collapse: It is possible to set that a collapse must be done after the importation, and its parameters (automatic or specified tolerance). If the collection of points is very big a collapse could be intersting to subsample them, and to avoid very close or repeated coordinates.
Triangulate: If this option is set then a Delaunay triangulation of the points will be done. (this triangulation is made in the xy plane projection)

KML


Menu: Files->Import->KML...
With this option it is possible to read files with the format KML (of Google Earth).

Extra options:
To projection: KML data is expressed as two dimension coordinates x,y that represents geographic latidude and longitude, it is possible to transform this information to other system:

  • None: Without any modification
  • UTM (Universal traverse mercator)
  • Mercator
  • PlateCarree

Calculix


Menu: Files->Import->Calculix...
Reads a Calculix geometry (.fbd extension).
Calculix is an structural solver, this format consists of a collection of Calculix commands and it is mainly used to store geo-
metrical information like points, lines, surfaces and bodies, and also could assign meshing information like element type or number of structured divisions on lines.
This importer is implemented as a Tcl plugin.

NASTRAN mesh

Menu: Files->Import->NASTRAN mesh...
With this option it is possible to read a file in NASTRAN format (version 68), with GiD accepting most of its entities, which are:
Entity name ( Notes)
CBAR CBEAM CROD CCABLE CBUSH CELAS1 CELAS2 CELAS3 RBAR (translated as 2 node bars)
CQUAD4 CQUADR
CHEXA
CTETRA
CPENTA
CTRIA3 CTRIAR
CONM1 CONM2 (translated as 1 node element)
CORD1C CORD1R CORD1S
CORD2C CORD2R CORD2S
GRID
There are two options that can be used when reading a mesh if GiD already contains a mesh:

  1. Erasing the old mesh (Erase);
  2. Adding the new mesh to the old one without sharing the nodes; the nodes will be duplicated although they may occupy the same position in the space (AddNotShare).


The properties and materials of elements are currently ignored, because of the difficulties in associating the NASTRAN file properties with the requirements of the analysis programs. Therefore, you have to assign the materials "a posteriori" accordingly. However, in order to make this easier, the elements will be partitioned in different layers, each with the name PIdn, where n is the property identity number associated with the elements as defined in the NASTRAN file. Note that CELAS2 elements do not have associated property identities so these will be created by default when the file is read.

STL mesh


Menu: Files->Import->STL mesh...
With this option it is possible to read a mesh in STL format. The STL binary format is also supported.
The variable ImportTolerance (see Preferences ) controls the creation of new points when the file is read.

VRML mesh


Menu: Files->Import->VRML mesh...
With this option it is possible to read a mesh in VRML 2.0 format. The compressed gzip format is also supported.

3DStudio mesh


Menu: Files->Import->3DStudio mesh...
With this option it is possible to read a mesh in .3ds 3DStudio format.

CGNS mesh


Menu: Files->Import->CGNS mesh...
With this option it is possible to read a .cgns mesh with CGNS binary format. CGNS is an standard format, specialized for the storage and retrieval of CFD (computational fluid dynamics) data.

GiDML mesh

Menu: Files->Import->GiDML mesh...
With this option it is possible to read the input and output meshes stored in a .gidml file in order to visualize it within GiD.
GiDML is the input/output format (HDF5 based) for GiD Mesh Library.
See https://www.gidhome.com/gid-plus/gidml


GiD mesh


Menu: Files->Import->GiD mesh...
With this option it is possible to read a GiD ASCII mesh (saved with Export GiD Mesh) in order to visualize it within GiD.
It is also possible to read a new mesh and add it to the existing one. In this case, you are prompted to keep the former one or join it to the new mesh.
The format of the file describing the mesh must have the following structure:
mesh dimension 3 elemtype tetrahedra nnode 4
coordinates
1 0 0 0
2 3 0 0
3 6 0 0
4 3 3 0
5 3 1.5 4
6 3 1.5 -4
7 1.5 0 2
end coordinates
elements
1 1 2 4 5 1
2 2 3 4 5 1
3 1 4 2 6 1
4 2 4 3 6 1
5 1 2 5 7 1
end elements
The code nnode means the number of nodes per element and dimension can be either:

  • 2: 2 dimensions. Nodes have just two coordinates.
  • 3: 3 dimensions. Nodes have three coordinates.


Where elemtype must be:

  • Linear
  • Triangle
  • Quadrilateral
  • Tetrahedra
  • Hexahedra
  • Prism
  • Pyramid
  • Point
  • Sphere
  • Circle


For sphere and circle elements after the connectivities the radius must be specified, and for circle elements also the three normal components could be written (z direction is considered by default)
Every element may have an optional number after the definition of the connectivity. This number usually defines the material type and it is useful to divide the mesh into layers to visualize it better. GiD offers the possibility of dividing the problem into different layers according to the different materials through the option Material (see Layers and groups (only Preprocessing) ). For sphere elements is necessary to additionally specify its radius.
Note: The = sign is optional, but if it is present it is necessary to leave a space.
If it is necessary to enter different types of elements, every type must belong to a different mesh. More than one mesh can be entered by writing one after the other, all of them in the same file. The only difference is that all meshes except the first one have nothing between coordinates and end coordinates. They share the first mesh's points. Example: to enter tetrahedron elements and triangle elements,
mesh dimension = 3 elemtype tetrahedra nnode = 4
coordinates
1 0 0 0
2 3 0 0
3 6 0 0
4 3 3 0
5 3 1.5 4
6 3 1.5 -4
7 1.5 0 2
end coordinates
elements
1 1 2 4 5 1
2 2 3 4 5 1
3 1 4 2 6 1
4 2 4 3 6 1
5 1 2 5 7 1
end elements
mesh dimension = 3 elemtype triangle nnode = 3
coordinates
end coordinates
elements
1 1 2 4 1
2 2 3 4 1
3 1 4 2 1
4 2 4 3 1
5 1 2 5 1
end elements


Surface mesh


Menu: Files->Import->Surface mesh...
With this option a mesh can be read from a file in GiD or STL format. Elements of this mesh must be triangles or quadrilaterals. This mesh is converted by GiD into a set of surfaces, points and lines. The geometric definition of surfaces is the mesh itself, but GiD treats them as truly geometric entities. For example, these surfaces can be used as the boundary of a volume, and a new mesh can be generated over them.
You are asked for the value of an angle. An angle between elements bigger than this value is considered to be an edge, and lines are inserted over them. As a consequence, a set of boundary and interior lines are created and attached to the surfaces to mark their edges.


Ply mesh


Menu: Files->Import->Ply mesh...
With this option it is possible to read files with format Ply (Stanford mesh). Generally, it saves polygons.
The variable ImportTolerance (see Preferences ) controls the creation of new points when the file is read.

OBJ Wavefront mesh


Menu: Files->Import->OBJ Wavefront mesh...
With this option it is possible to read mesh files with obj format (Wavefront Technologies).
The variable ImportTolerance (see Preferences ) controls the creation of new points when the file is read.

Vtk voxels


Menu: Files->Import->Vtk voxels...
GiD can import a mesh from a file with Vtk structured data point format (http://www.vtk.org/pdf/file-formats.pdf). This format represent a scalar field over a rectilinear 3D grid.
Extra options:

In the "Vtk voxels read" dialog box we can specify the isosurface value for the boundary of the body we want to extract from the volume. Besides we can choose among 3 different methods:

  • Marching cube: the well known method for isosurface extraction is applied an the result is a triangle mesh on the boundary of the body.
  • Uniform Hexahedra: an uniform mesh of hexahedra fited to the boundary is generated applying a dual .
  • Orthogonal Hexahedra: an orthogonal mesh of cubes is extracted from the volume selecting all the voxels withing the body bounded by the isosurface value.

XYZ nodes


Menu: Files->Import->XYZ nodes...
With this option it is possible to read a set of mesh nodes. This format is ASCII and consists in the coordinates of the nodes separated by spaces.
Note: If only 2 coordinates are specified, z=0 is assumed.

Extra options:
Triangulate: If this option is set then a Delaunay triangulation of the nodes will be done. (this triangulation is made in the xy plane projection)


UNV


Menu: Files->Import->UNV...
With this option it is possible to read I-DEAS UNV format, usually with extension .unv or .uff.
This importer is implemented as a pure Tcl plugin, with limited features (only some UNV entities are supported)
It converts the UNV information into a preprocess mesh of bars, and an auxiliary post.res file with the structural modal analysis results for postprocess (natural vibration modes)


STAR-CD


Menu: Files->Import->STAR-CD...
With this option it is possible to read STAR-CD mesh files
This importer is implemented as a pure Tcl plugin, with limited features.
accepted mesh files
.vrt -> vertex file, converted into preprocess mesh nodes
.bnd -> boundary elements, converted into preprocess mesh triangles or quadrilaterals
.cel -> body elements, converted into preprocess mesh prisms or hexahedra
Files Menu>Import>Preprocessing>Topography
This tool allow to get the topography of a region obtained from Internet.

It is possible to navigate pressing the arrow buttons and increasing the level of detail, and also setting the latitude and longitude, or the name of some place.
It creates a grid of surfaces or quadrilateral elements.


RASTER GDAL


Menu: Files->Import->GDAL...
With this option it is possible to read most kind of raster image formats, and convert them to a grid of squares z(x,y).
The typical use is to convert topographic images into a structured mesh.
This importer is implemented as a Tcl plugin, using the GDAL package (Geospatial Data Abstraction Library).
Some of the allowed raster formats are .tif,.png,.gif,.jpg, GIS Arc/Info grids, etc.
Raster images are a 2D structured grid of NxM points with values or each point, like the RGB color or current images, to encode topographical information like height, or other kind of data like land use.
There are some two extra options:
Create geometry: If it is selected then they are created geometrical entities (points, lines, surfaces)
Create mesh: they are created preprocess mesh entities (nodes and quadrilaterals)
Convert Arc/Info ASCII: write a new file with .txt extension in Arc/Info ASCII format
Increment: To allow subsampling data for big files, jumping by this value rows and columns of original data. It is set to 1 by default to take into account all data.


EMA3D


Menu: Files->Import->EMA3D...
With this option it is possible to read CADfix - EMA3D cartesian mesh files, with .emin extension.
This importer is implemented as a pure Tcl plugin, with limited features.
The file information is converted into a preprocess cartesian mesh of lines, quadrilaterals or hexahedra
Extra options:
Compressed: if this option is set then groups of contiguous elements are converted to a single line, rectangle or hexahedron, to represent the same shape with less entities.


Abaqus


Menu: Files->Import->Abaqus
With this option it is possible to read Abaqus mesh files, with .inp extension.
This importer is implemented as a pure Tcl plugin, with limited features.


Gcode


Menu: Files->Import->Gcode
With this option it is possible to read Gcode mesh files, with .gcode, .ncc, .ngc, .tap extension.
Gcode is a format to to control automated machine tools (3D printers, milling machines)
This importer is implemented as a pure Tcl plugin, with limited features.


Collada


Menu: Files->Import->Collada
With this option it is possible to read collada mesh files, with .dae extension.
COLLADA (COLLAborative Design Activity) is an interchange format, xml-based for interactive 3D applications.
This importer is implemented as a pure Tcl plugin, with limited features.
It allow to import it as a regular mesh, otherwise the mesh data and attached textures is handled at Tcl scripting variables level, and the textures are drawn on the mesh.

Exodus II


Menu: Files->Import->Exodus II
With this option it is possible to read Exodus II mesh files, with .e extension.
EXODUS II is a model developed to store and retrieve data for finite element analyses.
The EXODUS II library is maintained in the Sandia National Laboratories Engineering Analysis Code Access System (SEACAS)
This importer is implemented as a pure Tcl plugin, with limited features.
EXODUS II files can be written in two formats: netCDF or HDF5 (more modern)
The plugin allow to read/write only the HDF5 version


Batch file


Menu: Files->Import->Batch file...
Sometimes, you may wish to organise a number of commands into a group outside GiD, ready to be implemented in one go. To do so, commands can be written in a file and GiD will read this file and execute the commands. These commands are the same ones as are used in GiD when entered in the command line or using the commands in the Right buttons menu.
Example: Many points have been digitalized and their coordinates saved in a file. These points are to be joined with straight lines to create the outline of the geometry. To do so, the file would look similar to this:
geometry create line
3.7 4.5 8
2 5 9
4,5,6
...
1 7 0.0
escape
A batch file can also be loaded into GiD by giving its name with the option -b when opening GiD (see Invoking GiD). Another way to read batch files to create dynamic presentations is with the Read batch window (see Read batch window). One GiD session can be registered in a batch file. This can be useful for checking the batch commands or to repeat one session (see Preferences ).
BATCH FILE COMMANDS
There are some special commands to be added to a batch file that are treated differently from regular GiD commands. Their format is one or several words after the control string ***** (five asterisks) and everything in one line.

  • Write a log file

*****OUTPUTFILENAME filename
filename is substituted with a real file name where all the session warnings (those which appear in the GiD messages warning line) are written. This can be useful when running GiD in batch mode with the option -n (see Invoking GiD) and GiD output is desired.

  • Execute a Tcl command in a batch file

*****TCL tcl_command
Note: If this command is used in a batch file and GiD is invoked with the option -n, it will not work. So that Tcl commands are executed when GiD is run without a window, you should use the -n2 option (see Invoking GiD).

  • Insert comments in the code of a batch file

geometry create line 1,2
*****COMMENTS this is a comment
2,3 escape

  • Print messages in the lower GiD messages line

geometry create line 1,2
*****PRINT This is a message that will appear in the messages line
2,3 escape

  • Print messages in a window

geometry create line 1,2
*****PRINT1 This is a message that will appear in a new window
2,3 escape


Insert GiD model


Menu: Files->Import->Insert GiD model...
This command lets you insert one previously created GiD model inside another one. It imports the geometry, layers, mesh and groups information. Problemtype information is neglected.
Entities from the old and the new model are not collapsed.
You can perform one Collapse operation (see Collapse) to join the old and new models.

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