Use an Import node (
) to import a mesh from a file or from another meshing sequence or mesh part. It is only possible to import a mesh to a meshing sequence under a
Mesh node if the geometry sequence is empty. If the sequence already contains a mesh, the imported mesh is added to the existing mesh, forming an assembly. If you use this
Import node in a mesh part, you can then use it in a geometry sequence through an
Import node under a
Geometry node.
To import a mesh, right-click a Mesh node or a
Mesh Part node and select
Import. Then enter the properties for the import using the following section:
In the Source list, choose the type of data to import:
Any importable file,
Meshing sequence, and
COMSOL Multiphysics file are always available. In addition, you can choose
STL/VRML file in 3D and
NASTRAN file in 2D and 3D.
For file import, specify the filename in the Filename field or click the
Browse button. For import from another mesh in the model, select the meshing sequence from the
Source list below. To import a meshing sequence, click the
Import button. For a mesh part, the
Import button is not needed and is therefore disabled. If you have changed some property, the software automatically re-imports the mesh when you click a build button.
In 3D, you can import 3D meshes and planar 2D meshes from COMSOL Multiphysics files (.mphtxt or
.mphbin). Planar 2D meshes, imported to a 3D component, always appear at
z = 0.
When you import a mesh from a COMSOL Multiphysics file that contains mesh selections, you need to select the Import selections check box to import the selections together with the mesh. If you choose to import mesh selections, corresponding selections are created and appear in the
Domain Selections,
Boundary Selections,
Edge Selections, or
Point Selections sections, depending on space dimension and the entity level for the imported selections. You can use the imported selections, for example, to add as a selection to a data set or plot during postprocessing. See also
Domain Selections, Boundary Selections, Edge Selections, and Point Selections below.
To import mesh and material data from a NASTRAN file, select Mesh and materials in the
Data to import list. In this case, COMSOL Multiphysics creates
Material nodes corresponding to the data in any MAT1 and MAT10 entries in the file. Furthermore, the thickness data of any PSHELL entry in the file is stored in a
Variables node as long as it is greater than zero. To simplify the use of this data in physics interfaces, such as the
Shell interface, an
Explicit selection, which contains all boundary faces associated with PSHELL entries, also becomes available. If the material data is not required, select
Only mesh to import the mesh only.
To use material data in the file to determine the partitioning of the elements, select the Partition according to material data check box (selected by default). Choose
Create selections to automatically generate selections corresponding to the groups of domain and boundary elements in the file. If you do this, corresponding selections are created and appear in the
Domain Selections or
Boundary Selections sections, depending on the entity level for the imported selections. These selections become available for specifying geometric entities throughout the component — for instance, in Material nodes and physics interfaces. Choose
Allow partitioning of shells to allow the boundary partitioning algorithm to split the boundary entities that are defined based on the data in the file into smaller parts. Both options are selected by default.
These settings are available with the following options from the Source list:
COMSOL Multiphysics file,
STL/VRML file, and
NASTRAN file.
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Select Automatic to let the software partition the boundary elements into boundaries automatically (the default setting).
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Select Minimal to make a minimal boundary partitioning. This is useful when you import a mesh from a measured geometry or a NASTRAN mesh with a predefined boundary partitioning. The automatic face partitioning is not desired then.
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Select Manual (in 2D) or Detect boundaries (in 3D) to manually control the partitioning. Both choices add a set of parameters, which make it possible to influence the result of the partitioning algorithm; for the Detect boundaries case in 3D, the Detect Faces and Detect Edges sections appear, containing settings for controlling the face and edge partitioning, respectively.
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The Repair tolerance list is available when the
Source list is set to
STL/VRML file. The repair tolerance assures that the imported mesh contains no holes and no triangles with sides shorter that the tolerance. From the Repair tolerance list, select one of these options:
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Automatic (the default), to use a default tolerance value ( 10−8).
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Relative, to specify a Relative tolerance (default: 10−8). The relative tolerance value must be smaller or equal to 1.
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Absolute, to specify an Absolute tolerance (default: 10−8).
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If the Detect planar faces check box (3D) or the
Detect straight edges check box (2D) is selected (both are selected by default), the mesh import detects (approximately) planar faces or straight edges, respectively. The minimum size of a straight or planar boundary entity, relative to the entire boundary, can be set using the
Minimum relative length field (2D) and
Minimum relative area field (3D). The maximum accepted angle (in degrees) between elements for a boundary to be considered straight or planar can be set using the
Maximum neighbor angle field. If the
Detect adjacent fillet faces check box (3D) is selected, the algorithm also searches for adjacent groups of boundary elements that form cylindrical faces.
If the Detect planar edges check box is selected (it is selected by default), the mesh import detects (approximately) planar edges. The
Detection parameter specifies to which extent the operation should search for planar edges. Use the slider to tune the detection level, where
Strict means that only fully planar edges are searched for, and
Tolerant means that the algorithm searches for planar edges with a wider tolerance. You can also enter the parameter value directly as a value between 0 (strict) and 1 (tolerant).
If the Detect straight edges check box is selected (it is selected by default), the mesh import detects (approximately) straight edges. The
Detection parameter specifies to which extent the operation should search for straight edges. Use the slider to tune the detection level, where
Strict means that only fully straight edges are searched for, and
Tolerant means that the algorithm searches for straight edges with a wider tolerance. You can also enter the parameter value directly as a value between 0 (strict) and 1 (tolerant).
From the Minimum edge length list, choose on of the following options:
Automatic (the default),
Relative, or
Absolute to specify the minimum required length of an edge to be detected. If you select
Relative, specify a minimum relative length in the
Minimum relative length field that appears, and if you select
Absolute, specify a minimum absolute length in the
Minimum absolute length field that appears.
In these sections, imported mesh selection appear. In the Name column, the name of each selection appears. For COMSOL Multiphysics file import, each name is by default the name of the selection in the imported file, which appears in the
Name in file column. Select the name in the
Name column to highlight the selection in the
Graphics window. You can change the name of a selection by editing the corresponding table entry in the
Name column. Note that not all of these selection sections are available for all space dimensions.
