1.6 Graphical Picking
Many functions in the ANSYS program involve graphical picking - using the mouse to identify model entities and coordinate locations. There are three types of graphical picking operations: Mouse Button Assignments for Picking
Mouse button assignments during any picking operation are as follows: Hot Spots
Hot spots are the locations on an entity that identify it for retrieval picking. For example, if two elements are adjacent, the element that is picked is the one whose hot spot is closest to the mouse pointer. For areas, volumes, and elements, the hot spot is at a location near the centroid. Lines have three hot spots: one in the middle and one near each end.
If the hot spots of two or more entities are coincident, picking the coincident entities brings up a "Multiple Entities" dialog box (Fig. 1.29). Press the Next or Prev button to "cycle through" the coincident entities until the desired entity is highlighted. Then click OK to pick that entity.
image
Fig. 1.29 Multiple Entities Dialog Box
1.6.1 Locational and Retrieval Picking
Whenever graphical picking (clicking on a menu topic ending with the + symbol) is used, the GUI brings up a picking menu, sometimes known as the picker. Figure 1.30 shows the picking menus for locational and retrieval picking. In this example, creating keypoints by picking their locations on the working plane is a locational picking operation, and picking those keypoints to apply a load on them is a retrieval picking operation.
image
Fig. 1.30 Picking Menus for Locational and Retrieval Picking
1.6.2 Query Picking
The picker can be used to "Query" data on the model at any time during the analysis. Querying means that, for any picked point on the model, ANSYS will retrieve or calculate specified items from the database and display them. This information can be displayed in an output window, or it can be applied to the model as 3-D annotation. Query picking is a retrieval picking function, with the selection box items varying according to the requested data. The model and results query pickers are discussed in the following sections.
1.6.2.1 The Model Query Picker
The model query picker allows to access model information by picking displayed entities. It also performs basic computations to provide simple geometric/loading information. The model query picker can be used to obtain information about the model while building it. This is helpful when building on to an existing model, or for applying forces or loads that are dependent on the model data. The model query picker can be accessed by choosing Utility Menu> List> Picked Entities, at any time during the analysis.
Annotation
When the model query picker is used to obtain model information, ANSYS displays the information in a text window. That information can also be applied to the model as 3-D annotation by checking the "Generate 3D Anno" box on the picker. The annotation is applied with the appropriate units displayed, and arrows and leaders are attached where necessary. 3-D annotation, unlike 2-D, will attempt to retain the proper positioning on the appropriate entities, even when the model is rotated or resized.
The overall 3-D dimensions of the model are defined by a bounding box. If portions of the model's bounding box lie outside of the visible area of the graphics window, it can affect the placement of the 3-D annotations. Zooming out will usually overcome this problem.
Modify query annotation using Utility Menu> PlotCtrls> Annotation> Create 3D Annotation. Select "Options" to modify the typeface and move, copy, or resize the annotation.
Action Buttons
Tips on Using the Model Query Picker
The model query picker is accessible at any time during the analysis. It is useful for determining model database information that would require hand calculations to determine. The computations performed by the picker are not displayed until OK or APPLY is pressed.
The items selected by the picker are highlighted before they are actually selected. Hold the left mouse button down and move the pointer around the model to ensure that the proper entity is selected. The analyst can select multiple items, with no computations being performed or annotation applied until OK is clicked. The commands and operations performed by the model query picker are not written to the log file.
The annotation that is generated during the preprocessing stage can be displayed at any time during the analysis. This information is not modified or updated during the course of the analysis, and can become invalid. For instance, when a shape is deformed by the applied forces, the area and volume annotations created before applying the force will not change, and the information displayed may be incorrect.
1.6.2.2 The Results Query Picker
The most convenient way to review results for specific points on the model is by using the results query picker. Querying means that, for any picked point on the model, the ANSYS program will retrieve a specified results data value from the database and display it. Access the results query picker by choosing Main Menu> General Postproc> Query Results. The analyst can query nodal or element solution data.
When this GUI path is choosen, the results query picker for element solution data appears. This menu has most of the same items as the locational and retrieval picking menus: Annotation
The results query picker retrieves solution data from the database and displays it in a text window. That information can be applied to the model as 3-D annotation by selecting the “Generate 3D Anno” box on the picker. The annotation is applied with the appropriate units displayed, and arrows and leaders are attached where necessary. The overall 3-D dimensions of the model are defined by a bounding box. If portions of the model's bounding box lie outside of the visible area of the graphics window, it can affect the placement of the 3-D annotations. Zooming out will usually overcome this problem. Unlike the model query picker, the results query picker displays the actual data on the model as the mouse pointer is moved over the different entities. This function is available only from the General Postprocessor.
Action Buttons