Home
Pre-Processing
Simcenter STAR-CCM+ solves physics problems on a computational mesh. To provide this mesh, you first define geometry using internal or external tools, and then create a mesh pipeline whose operations generate the mesh in repeatable steps.
Modeling Geometry
This part of the User Guide describes how to use 3D-CAD, the parametric solid modeler available within Simcenter STAR-CCM+. It also describes the features and tools available for further preparation of the geometry model and its surfaces.
Repairing CAD Geometry
The Geometry Repair tool provides diagnostic checks for assessing the validity of geometry and the means to repair the geometry automatically.
Geometry Error Categories
The Geometry Repair tool identifies Parasolid invalidities and groups the various errors into 8 categories.

Share

Link: copied

Breadcrumb: copied

Pre-Processing
Simcenter STAR-CCM+ solves physics problems on a computational mesh. To provide this mesh, you first define geometry using internal or external tools, and then create a mesh pipeline whose operations generate the mesh in repeatable steps.
- 3D-CAD
  3D-CAD is a feature-based parametric modeler within Simcenter STAR-CCM+ that allows you to build geometries from scratch. The geometries that you create with 3D-CAD are stored as 3D-CAD models, which you can then convert to geometry parts for integration with the meshing and simulation process.
- Modeling Geometry
  This part of the User Guide describes how to use 3D-CAD, the parametric solid modeler available within Simcenter STAR-CCM+. It also describes the features and tools available for further preparation of the geometry model and its surfaces.
  - Preparing the Geometry
    In general, a Simcenter STAR-CCM+ analysis requires one or more geometry parts from which you define the spatial construction of the regions. Simcenter STAR-CCM+ allows you to create geometry parts directly using the built-in 3D-CAD modeler, or import geometry from a wide range of source formats.
  - Importing Geometry
    One of the possible starting points for the meshing process is to import surface data.
  - Understanding Geometry Parts
    You can use the geometry parts manager node to control what parts are meshed and included in the simulation downstream.
  - Manipulating Parts
    Simcenter STAR-CCM+ allows leaf-level parts to be manipulated in several different ways once they have been imported or created.
  - Part Contacts
    Part contacts define the connection between two part surfaces. The meshers aim to generate a conformal mesh at the contact, which then becomes an interface in the physics region.
  - Repairing CAD Geometry
    The Geometry Repair tool provides diagnostic checks for assessing the validity of geometry and the means to repair the geometry automatically.
    - Geometry Error Categories
      The Geometry Repair tool identifies Parasolid invalidities and groups the various errors into 8 categories.
  - Displaying the Geometry
- The Surface Repair Tool
  The Surface Repair tool diagnoses errors in, and provides repair tools for, tessellated surfaces and part curves. The same tool allows you to reorganize discretized geometry by searching for face-based features and attributes then assigning the results to new or existing part surfaces or curves.
- Defining the Regions Layout
  An essential part of the process in setting up your simulation is to define the relationship between geometry parts and regions, boundaries, and interfaces.
- Meshing
  A mesh is a discretized representation of a geometric domain. This domain can include real-world geometry, its content, and its surrounding environment.

Geometry Error Categories

The Geometry Repair tool identifies Parasolid invalidities and groups the various errors into 8 categories.


Diagnostics Category	Description
Self Intersection	Indicates errors that are associated with edges that cross each other and faces that self-intersect. In most cases, the Geometry Repair tool can fix these types of error by merging edges and vertices to remove the self-intersection.
Invalid Spline Definition	Indicates errors that are associated with poorly defined or incomplete sets of points that define a spline.
Invalid Geometry	Indicates errors in the relationships between entities in the geometry model. This type of error can also indicate that the model is corrupt. The Geometry Repair is likely not able to repair corrupted geometry. In this case, you are advised to return to the native CAD package to see if the errors can be repaired.
Tolerant Geometry	Indicates errors that are associated with loose tolerances of vertices, edges, and faces in the geometry. Loose tolerances can result in loss of data/definition of the geometry. For example, a high tolerance can prevent a gap from being recognized as a gap and ultimately stopping the gap from being closed. If the Geometry Repair tool cannot repair tolerance issues, you are advised to return to the native CAD package and look at the tolerance settings and tighten up the tolerance settings there.
Overlapping Entities	Indicates errors that are associated with overlapping faces. This type of issue could be due to tolerance issues in the geometry model.
Topology Errors	Indicates errors that are associated with fundamental errors in the entity definition. For example, faces that have edge loops that are defined in the opposite direction to other edges in the geometry.
Non-Manifold Geometry	Indicates errors where the geometry contains non-manifold vertices or non-manifold edges. A vertex is non-manifold if any of its connected faces have no other link with the rest of its connected faces apart from the vertex. An edge is non-manifold if it is shared by two or more faces.
Bad Part/Assembly/Instance Data	Indicates errors that are associated with the assembly definition, and the parts and instances within a model. This type of error is typically caused by poorly defined shells and solids. Another cause could be issues with instancing and missing information from the parts and assemblies.