The Select command is very useful in managing complicated drawings where we want to incorporate certain changes such as moving, copying, erasing, and changing properties for specific entities. The Select command groups entities into a selection set for use in subsequent commands. Let us see how efficiently we can use select command options in “CHPROP” command for changing properties of a certain group of entities in a drawing.
Consider a particular drawing containing a number of entities and blocks. To change the properties of some specific entities that are scattered in the drawing, selecting each entity to change its property would be a tedious job. This is where the “Select by properties” option comes in useful. The select command options work the same way with other editing commands such as move, copy, mirror, scale, rotate, and array, where we want to select a group of entities at a time.
The functions of different tools displayed in the Select prompt box are as follows –
|Select all entities ||Selects all entities in the current drawing.|
|Add to set ||Adds to the selection set.|
|Previous selection ||Selects the previous selected items.|
|Last entity in drawing ||Select the last created entity in the present drawing.|
|Window-Inside ||Selects entities contained entirely within a rectangular selection window.|
|Crossing window ||Selects entities contained within or crossing the boundary of a rectangular selection window.|
|Outside window ||Selects entities falling completely outside a rectangular selection window.|
|Window polygon ||Selects entities contained entirely within a polygon selection window.|
|Crossing polygon ||Selects entities contained within or crossing the boundary of a polygon selection window.|
|Outside polygon ||Selects entities falling completely outside a polygon selection window.|
|Window circle ||Selects entities contained entirely within a circular selection window.
|Crossing circle ||Selects entities contained within or crossing the boundary of a circular selection window.|
|Outside circle ||Selects entities falling completely outside a circular selection window.|
|Point ||Selects any closed entities that surround the selected point.|
|Fence ||Selects entities crossing a line or line segments.|
|Select by properties ||Selects entities that match a particular set of properties - for example, all entities on a particular layer or drawn in a certain color.|
|Selection methods… ||Selecting this will display the drawing setting – Coordinate input prompt box where we can specify the selection method.|
|Cancel ||Quits the command.|
Among all options in the Select command, probably the most versatile option is “Select by properties”. This option enables us to select all the entities scattered randomly in the drawing at the same time with accuracy. In absence of this command, it would be almost impossible to select entities within a drawing using ordinary selection methods.
Let us see how “Select by properties” proves to be beneficial.
To change properties of certain objects in a current drawing at a time, we can use the “CHPROP” command.
After invoking ”CHPROP” command the following prompt box will be displayed-
The “Select by Properties” option of the “CHPROP” command helps us to select all the objects in the current drawing having similar properties.
On selecting the “Select by Properties” option the following prompt box will be displayed -
Now we can select the entities based on the eight properties (Color, Layer, Linetype, Name, Thickness, Type, Value, and Width) and can change their properties one at a time.
Suppose we select the entities based on the layer. After specifying the layer name, all the entities in that layer get highlighted.
On pressing enter, the command window will prompt us for the “Property to change”.
The command window is shown below –
We can change any of the properties shown in the command window by entering the appropriate property and the change will take place at the same time on all the entities of the chosen layer.
EXERCISE USING THE CHPROP COMMAND
In this example we will use the “CHPROP” command to change the color of all the entities present in a particular layer named ”Textsmall”.
- Open the drawing “Bailey Bridge-up.dwg” file. The drawing should look as shown in the following figure:
- Switch to the Model space and invoke “CHPROP” command.
- Choose “Select by Properties” from the CHPROP prompt menu. This will show the options under Select by properties.
Choose option “Layer” from the prompt box. Now the command line will prompt for “layer(s) name to select”, type “TextSmall”. Entities in the “TextSmall” layer will be selected.
Press enter. The command window displays the following –
- Type C for Color and press enter.
CADopia will prompt for, – New Color<130>:
- Type Y for Yellow and enter twice to end the command.
Now you will notice the entities in the layer “TextSmall” have been changed to Yellow. Besides changing the color of the entities you can even change the properties shown in the “Property to change” prompt.
- Now switch back to the Paper space. You will find the drawing as shown below.
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