This option permits manual resetting or simple inspection of the permitted error range. The sensitivity of the cursor for locating a grid node is reset automatically at intervals by the Editor to suit the local grid resolution. This process is usually transparent to the user, but occasionally the required point may not be identified successfully. If the wrong point is moved, deleted, etc., the permitted cursor error limit is too coarse. However, the sensitivity will be reset automatically in accordance with the length of connections to the node actually selected, and since this node will almost always be close to the required node, it is usually possible to select the right node by cancelling the faulty editing operation and simply repeating the original choice. The same remarks apply to deleting a line and to INSERT and EXCHANGE operations, in all of which the mid-point of a connection between nodes has to be picked out with the cursor.
On the other hand, cursor sensitivity is occasionally too fine to pick up any point, for instance when interest is transferred from an area of the grid with fine resolution to a part where triangles are much larger. In such cases, the message:
will appear briefly, after which the user will be prompted again to choose the point. Usually a second attempt will be successful because the cursor error range is automatically increased by a factor of 3 if no node is found.
If a required point still cannot be picked out with the cursor after several tries, choosing the {TOP.CONFIG}CURSOR option will bring up a message of the form:
where 0.2267 (or whichever number appears) is the current error range in problem length units. The user can then enter a different value or press RETURN to proceed using the current value.