Limits Tab
The options on this tab enable you to set limits on AutoGEM when it is creating and editing elements.
In general, you should use the defaults on the tab. They provide acceptable elements for the greatest number of models. If AutoGEM encounters any problems when generating elements, you can then change some of the settings on the tab to fine-tune the elements that AutoGEM creates.
The tab contains the following items:
• Limits for—Enables you to specify what kind of limits you are setting. Select one of the following items from this list:
◦ Creating—AutoGEM limits the angles on elements that it creates either during initial modeling or as the result of a geometry change.
◦ Editing—Editing limits are for element validity after smoothing or editing. A geometry shape change caused by a design variable change may cause an element to violate the creation limit. If an element violates the editing limit, select Re-mesh after each shape update in the Design Study Options dialog box and allow AutoGEM to create new elements after each shape update.
The limits on angles during AutoGEM element creation are set so that the elements converge well during the analysis. To retain the same element set during editing, the default editing limits are relaxed to reduce the element regeneration that is required.
These relaxed editing limits enable AutoGEM to move points, which makes it easier to maintain the original set of elements. When AutoGEM can edit elements by repositioning points, elements are less likely to become invalid and the model is less likely to require element regeneration.
• Allowable angles (degrees)—Enables you to set minimum and maximum
edge and face angles. By widening the spread of the default values, you can reduce the number of elements AutoGEM creates. For an example, see
Reducing the Element Count.
• Max. edge turn (degrees)—Enables you to set the maximum subtended edge angle. The lower the number you use in this entry box, the greater the number of elements AutoGEM creates.
• Validate—Enables AutoGEM to highlight elements that do not meet the limits.
• Default—Resets all the displayed values to the default values.