Selection Filtering includes Solids, Surface, Planes and Detail Menu elements. When you are working on complex parts that are made up of densely packed entities, filtering allows you to focus on the specific entities you want to select. Think of filtering as a transparent overlay that filters out the entities you do not want. This makes the entities you do want easier to access. This transparent filter does not, in any way, alter your drawing
 
Tips on Filtering

The Filter function can be accessed from the Edit pull-down menu, or from the Immediate commands under Tools>Options>Commands.

• When you use the Selection Menu, you are given two ways to filter: general and level. Both general  and level  let you filter out the entities you want to work with. Filtering speeds up the selection process. Also, when you use SINGLE, filter increases the reliability of your selection.

• General filtering allows you to target on entity and/or attribute types. Level filtering allows you specify selection from designated levels.

• When you choose ALL DSP>BY TYPE, or EX TYPE from the Selection Menu options, the filter dialog is displayed. The filter dialog box gives you exceptional control over your selection. You can choose to select by Entities, Line Styles, Line Widths, Colors, Level or flag #. You can use any or all of these attributes together to specify exactly what you want to filter on.

• Design Files will allow 64 user-defined colors.

• The Filter dialog box will be initialized with the current filter settings when called through the Set Filter Immediate Mode command (the keystroke for which will vary depending on what accelerator keyboard file you have loaded). However, the dialog box will be blank and not have any settings if no filter has been set previously, or if using the ALL DSP>BY TYPE and ALL DSP>EX TYPE selection methods.

• You can also view the current filter "on the fly" using the Set Filter Immediate Mode command. Be aware that there are conditions that will cause the Filtering dialog to have settings other than those you’ve personally set. For example, the Modify Trim/Break functions automatically set the filter to only include those entities it knows how to trim/break, and the Radial and Diameter Dimension functions automatically set the filter for arcs.