The two types of hard entities are hard edges and hard points. Hard entities are usually defined in the DesignModeler application or a CAD system.
A hard point is an embedded point in a face or edge. Hard points are captured by nodes during the meshing process. Hard points are not supported for the following mesh methods or controls:
A hard edge is an embedded edge in a face. There are two main types of embedded edges:
An edge in which one vertex of the edge touches the face boundary, but the other vertex does not touch a face boundary
An edge in which neither of the vertices touches the face boundary
Hard edges are not supported for the following mesh methods or controls:
2D or 3D inflation
Note:
If the methods and controls listed above are required in your mesh, insert a Virtual Topology and use the Simplify Faces option to remove the hard entities.
Other mesh methods have certain limitations in how hard points and hard edges are handled. For more information, refer to Limitations of Using Hard Entities with Other Mesh Controls.
Spot Welds
Spot welds are used to connect individual surface body parts together to form surface body model assemblies, just as contact is used for solid body part assemblies. Spot welds are usually defined as hard points in the DesignModeler application or a CAD system:
When a model is imported into the Meshing application, the mesher simply treats the hard points as embedded points.
Upon import to the Mechanical application, spot welds are automatically generated where hard points are defined in the model.
For related information, refer to Point in the DesignModeler help and Spot Welds in the Mechanical help.
Limitations of Using Hard Entities with Other Mesh Controls
Limitations of hard entities include the following:
3D inflation does not support hard entities of either type. If inflation is applied, a warning message is issued to indicate the hard entities were ignored.
2D inflation supports hard points only.
General Sweeping does not support hard points.
The MultiZone Quad/Tri and MultiZone mesh methods do not respect hard entities unless their topology is protected.
For the MultiZone mesh method only, the faces that contain the hard entities must be selected as source faces for the hard entities to be respected.
Hard edges may exist accidentally in a CAD model due to Boolean operations with tight tolerances or other such operations. These accidental hard edges may be undesired, in which case you should remove them by using the Virtual Topology: Face Simplify feature or defeaturing them within the DesignModeler application or a CAD system.