Mesh Refinement

There are many situations where you are more concerned with the accuracy in certain areas of a model than others. Therefore, you will want to have a fine mesh in those areas to ensure accurate results. However, if you create the surface mesh of the entire model with a fine mesh size, you may spend unneeded time analyzing the fine mesh in regions where the results are not as important to you.

The solution to this problem is to use refinement points. A refinement point specifies a region or volume of space in which a finer mesh will be generated. You can define mesh refinement by specifying an absolute size for the local mesh or a divide factor (size relative to the global mesh size). These refinements can be added in the FEA Editor environment using the following methods.

Refine an entire surface

Note: Applicable to CAD solid models only.

Use the following steps to specify a finer mesh over an entire surface of your CAD model.

1. Click Selection Select Surfaces and select one or more surfaces on which the same refinement parameters are appropriate.
2. Click Mesh Refinement Add to Selection, or right-click in the graphics window and click Add Surface Refinement. The surface refinement dialog box displays.
3. Specify the appropriate refinement parameters.
4. Click OK to complete the definition. A new entry displays under the Meshes Surface Refinement node in the browser.
5. Generate the mesh.

Note: You can combine surface refinements listed under Meshes in the browser, or you can move them from one surface refinement group to another. To do this, select one or more Part x / Surface y subheadings, right-click a selected subheading, and choose the Move fly-out submenu from within the context menu. Then, choose the group to which you wish to move the selected refinements. You can also drag and drop items from one surface refinement group to another one. Other common commands available from within the context menu are—Rename, Inquire, Edit, Cut, Copy, Paste, and Delete.

Refine along an edge

Note: Applicable to CAD solid models only.

Use the following steps to specify a finer mesh along an edge of your CAD model.

1. Click Selection Select Edges and select one or more edges along which the same refinement parameters are appropriate.
2. Click Mesh Refinement Add to Selection, or right-click in the graphics window and click Add Edge Refinement. The edge refinement dialog box displays.
3. Specify the appropriate refinement parameters.
4. Click OK to complete the definition. A new entry displays under the Meshes Edge Refinement node in the browser.
5. Generate the mesh.

Note: You can combine edge refinements listed under Meshes in the browser, or you can move them from one edge refinement group to another. To do this, select one or more Part x / Edge y subheadings, right-click a selected subheading, and choose the Move to fly-out submenu from within the context menu. Then, choose the group to which you wish to move the selected refinements. You can also drag and drop items from one surface refinement group to another one. Other common commands available from within the context menu are—Rename, Inquire, Edit, Cut, Copy, Paste, and Delete.

Refine around a point in space

Note: Applicable to CAD solid model meshes, surface mesh enhancement, and 2D mesh generation.

Use refinement points to refine the mesh within a spherical zone around each refinement point. You specify the radius of the sphere. Any elements within the sphere are refined, including elements on different parts.

Use the following steps to specify a finer mesh around a point.

1. Specify the location of the refinement points using one of the following methods.
   • If a mesh exists, click Selection Select Vertices. Select one or more vertices around which the same refinement parameters are appropriate. Click Mesh Refinement Add to Selection, or right-click in the graphics windows and click Add Refinement Points.
   • To apply refinement at construction vertices, click Selection Select Construction Vertices. Select one or more construction vertices around which the same refinement parameters are appropriate. Click Mesh Refinement Add to Selection, or right-click in the graphics windows and click Add Refinement Point.
   • If you know the coordinate of the refinement point, such as the center of a hole, right-click in the graphics window with nothing currently selected and click Add Refinement Point. Enter the X, Y, and Z coordinates of the refinement point within the dialog box that appears.
   • If you are working in a drawing plane, for 2D mesh generation, right-click in the plane at the appropriate location and click Add Refinement Point.
2. Specify the appropriate refinement parameters.
3. Click OK to complete the definition. A black dot displays on the model. Also, a new entry displays under the Meshes Refinement Point node in the browser.
   Tip: There are three options to toggle the visibility of refinement points or their spherical refinement zones. Refinement points appear as black dots. Refinement zones appear as transparent orange spheres at each refinement point:
   • Click Mesh Refinement Visibility to toggle the visibility of the refinement points (black dots) on your model. This command does not affect the visibility of refinement spheres.
   • View Visibility Object Visibility Refinement Points: Toggles the visibility of the refinement points (black dots) on your model.
   • View Visibility Object Visibility Refinement Spheres: Toggles the visibility of the refinement zones (transparent orange spheres) on your model.
4. Generate the mesh.

Note: You can combine refinements points listed under Meshes in the browser, or you can move them from one refinement point group to another. To do this, select one or more Refinement Point x subheadings, right-click a selected subheading, and choose the Move to fly-out submenu from within the context menu. Then, choose the group to which you wish to move the selected refinements. You can also drag and drop items from one refinement points group to another one. Other common commands available from within the context menu are—Rename, Inquire, Edit, Cut, Copy, Paste, and Delete.

Modify or delete a refinement

To change the parameters for existing refinement points, you can select the points on your model, right-click, and click Edit. The appropriate refinement dialog box displays. For point, surface, and edge refinements, right-click the appropriate node in the browser and click Edit. You can also edit multiple refinements simultaneously, however, you can only change fields with the same input - fields with conflicting input are unavailable.

Alternatively, you can make changes in the Refinement Point Browser. Click Mesh Refinement Specify Nodes. You can change parameters (double-click the appropriate cell), delete individual points (highlight rows and click Remove), or delete all points (click Clear).

To delete an existing refinement, select the refinement, right-click, and choose Delete.

Refinement parameters

In the refinement dialog box, set the refinement parameters appropriate to your analysis.

• X, Y, Z specifies the coordinates of your refinement point. If you have multiple vertices selected, the coordinate fields are unavailable.
• Effective radius specifies the radius of the sphere, centered about the refinement point, within which all elements are refined regardless of their parent part.
• Mesh size specifies your target side length for elements within the refinement region. Beyond the refinement region, the mesh transitions to the normal mesh size. You can only specify a value smaller than the average mesh size.
• Divide factor specifies a number by which to divide the normal mesh size.

Regardless of the refinement method you use, the mesh size you specify is approximate. As the refinement process creates a whole number of elements, you can end up with more or less elements than you expect. This variation in number of elements is most prevalent when using the divide factor method on a narrow surface.

Use automatic refinement

This command is applicable to CAD solid models only.

The Mesh Refinement Automatic command will access the Automatic Refinement Points dialog. In this dialog, you can use the slider to specify the level of refinement you want to use. Moving the slider farther to the right will result in more refinement points. When you press the Generate button, the model will be inspected for short features. Refinement points will automatically be added in these regions. If you want more or fewer refinement points, drag the slider and click the Generate button again. Once applied to the model, these automatic refinement points behave the same as any refinement point; that is, they exist at a location in space and have fixed input. (You can change the input for individual points by using Mesh Refinement Specify Nodes.)

Once the model has the desired refinement points, click the Close button on the dialog, and then re-generate the mesh (Mesh Mesh Generate 3D Mesh).