Preparing Geometry for Meshing

Before Preparing Geometry for Meshing:

1. Provide the geometry to use in the simulation. There are two options:
   • Import CAD data or surface mesh

     See Importing Geometry.

   • Create a model using 3D-CAD

     See Creating Geometry Parts from 3D-CAD.

2. If you create a model in 3D-CAD, convert the 3D-CAD model to geometry parts.
   1. Right-click the Geometry > 3D-CAD Models > [3D-CAD Model] node and select New Geometry Part.

      The Parts Creation Options dialog appears.

   2. Click OK.

To Prepare Geometry for Meshing:

1. Apply any necessary boolean operations.
   1. Right-click Geometry > Operations > New and select one of the following Boolean operations:
      • Unite Parts

        Merges multiple overlapping/coincident parts into a single part.

      • Intersect Parts

        Creates a part from the common volume of the selected parts.

      • Subtract Parts

        Removes the geometry of chosen solid or sheet parts from the target part.

      See Performing Boolean Operations.

   2. Complete the properties of the [Boolean operation] dialog as required and click OK.

      Unexecuted Boolean operation nodes are now displayed under the Geometry > Parts and Geometry > Operations managers.

   3. Right-click the Operations > [Boolean operation] node and select Execute.
2. To perform a transformation on a geometry:
   1. Right-click on the Geometry > Operations node and select New > Surface Preparation > Transform.
   2. Right-click the Transform > Transforms node and select New > [Transform Control].
   3. You can perform multiple transformations within the same Transform mesh operation, by creating multiple Transform controls. See Transform Control properties.

      The Transforms are applied in the order in which they appear in the tree. To change the order, right-click the Transforms node and select Reorder..., then use the Reorder Transforms dialog as required.

   4. The Motion transform operation allows you to drive a motion transformation (Under Tools > Motion) so that the cumulative displacement of the object is applied to its root description. For more information, see Motion Transform Operation.
3. If there are holes or openings in the geometry, perform the Fill Holes operation before extracting the volume.
   1. Right-click the Geometry > Operations node and select New > Fill holes.
   2. Complete the properties of the Fill Holes operation dialog as required and click OK.

      Unexecuted Fill Holes nodes are now displayed under the Geometry > Parts and Geometry > Operations managers.

   3. Right-click the Operations > Fill Holes node and select Execute.

      See Fill Holes Operations for details of the operation properties.

4. If the imported geometry part represents the solid surrounding a fluid, and the fluid is the part being modeled, use the Extract Volume operation to create the Fluid part.

   See Extract Volume.

5. If faces of adjacent parts are in contact, use the Imprint operation to ensure that common surfaces of each part retain their own faces. A conformal mesh can still be formed between them.

   See the Imprint Parts Operation.

6. Define the region layout by assigning parts to regions.

   Note

   When you assign parts to regions and part surfaces to boundaries, the perimeters of the boundaries are marked internally as features for the remesher to preserve. Assigning parts to regions after an automated mesh operation means that a complete remesh is required, since the additional edges that are marked as features change the starting surface.

   See Regions Layout Workflow.

7. Set boundary types for each boundary.

   See Setting Types.

At the end of this task, you have a geometry that is ready for surface and volume meshing. However, if the geometry has multiple defects or unintentional gaps, you can use the Surface Wrapper before generating the surface and volume mesh.