In some cases ABAQUS/CAE is unable to differentiate between the object you have selected and other nearby or related objects. This ambiguity can arise as follows:
Imagine a small square surrounding the cursor. When you click an object, any other valid objects of the same type that fall inside this square are also considered to be possible selections. For example, if you select an edge that is positioned very close to another edge, ABAQUS/CAE may consider both edges to be possible selections.
The size of the square is independent of the monitor size, the viewport size, and the dimensions of the model. It also remains constant when you zoom in and out on your model. Therefore, you can select a specific object in the viewport more precisely by zooming in on your model to increase the distance between objects.
If your model is three-dimensional, imagine a line that is perpendicular to the screen and that passes through the cursor and into the model. When you select an object, any valid objects of the same type that intersect this line are considered to be possible selections. (Rotating your model may remove some of the ambiguity.)
ABAQUS/CAE reduces the potential for ambiguity by filtering your selection against the current procedure whenever possible. For example, if you are partitioning a cell, ABAQUS/CAE prompts you to select the cell to partition. When you make a selection, ABAQUS/CAE considers only cells to be a valid selection. Conversely, if you are creating a geometry set, ABAQUS/CAE considers cells, faces, edges, and vertices to be a valid selection and the potential for ambiguity is increased. In addition, preselection highlighting allows you to see exactly which object would be selected before you make the selection. Moving the cursor around the viewport may remove the ambiguity in the selection and result in ABAQUS/CAE highlighting the object of your choice. If the ambiguity remains, ABAQUS/CAE changes the cursor, adding ellipsis marks (...) to the right of the arrow, and highlights all the possible selections.
When your selection is ambiguous, ABAQUS/CAE displays buttons in the prompt area that allow you to cycle through all of the possible selections, as shown here:
