Fine Tuning Drawings and Grouping

5. Fine Tuning Drawings and Grouping

5.1 Hatching Command

You can hatch an area using a predefined hatch pattern. HATCH command fills an enclosed area & selected objects with a hatch pattern, solid fill, or gradient fill.

1. Type HATCH in the command line

Command: HATCH

(A dialog box appears)

2. Choose Hatch (on the top of dialog box)
3. Click on the 'Add: Pick Points'. Then, you will return to the drawing area, choose the area that you want to hatch
4. Press ENTER. You will now return to the dialog box again.
5. Choose the hatching pattern you like in 'Swatch'
6. Choose the angle and scale if you like.
7. Press 'OK' on the dialog box.

You will return to the drawing area with the select region being already hatched.

Before Hatching-

After Hatching-

5.2 Working with Layers

Layers are like transparent overlays over which you can organize & group various kinds of drawing information. The concept of layers is very significant in AutoCAD drawing & the appropriate use of layers can make your drawing very easier to work with. Basically, layers are the computer similar of tracing overlays on a drawing board. However, layers are much more useful & powerful because you can have many layers in a single drawing & also you can control the color, visibility, & linetype of layers independently.

In addition, layers can also be used for the following purposes:

1. To group information in a drawing by function & to enforce linetype, color, & other standards.
2. To manipulate the visibility of objects & to assign properties to objects.
3. Layers can be locked to prevent objects from being modified.
4. Change the name of a layer and any of its properties, including color and linetype, and you can reassign objects from one layer to another.
5. You can save the current layer settings in a drawing and restore them later.

The sequence of command:

1. Type LAYER in the command line.

Command: LAYER or LA

(A dialog box appears)

or

2. Click on the 'LAYERS' icon form the Layer Control Box located on the object properties toolbar.

Layer Options:

?- It lists layers, with states, colors, and linetypes.

Make- Creates a new layer and then makes it current.

Set- Sets the current layer.

ON- it turns on the specified layers.

OFF- it turns off the specified layers.

New- Creates a new layer.

Color- Assigns color to the specified layers.

Freeze- it completely ignores the layers during regeneration.

Ltype- Assigns linetype to the specified layers.

Thaw- Unfreezes the specified layers Ltype

Lock- it makes a layer read only preventing entities from being edited but available visual reference and osnap functions

Unlock- Places a layer in read write mode and makes available for edits.

Plot- it turns the LAYERS On for Plotting

No Plot- it turns the LAYERS Off for Plotting

LWeight- it controls the line weight for each layer

How to Create a New Layer?

- If you want to create a new layer, you need to click on

in the Object Properties toolbar, then a dialog box 'Layer & Linetype Properties' that is given below appears. In this dialog box you control both the Layer properties & Linetype properties. It depends on which tab you select. The Layer tab is selected by default. So, now you can click on 'New' button and then a new layer 'Layer1' will automatically created in the layer list below the default layer 0. As you can see in below dialog box, the new layer name is automatically highlighted so you can provide the new layer a more meaningful name that suits it. When you have given an appropriate name to the layer, hit the ENTER key to complete the operation. Now you have created a new layer with a suitable name.

As you can see in the dialog box that, by default the new layer has its color white & linetype 'continuous'. We will be talking about this in next topic.

Moreover, there are some limitations to be considered when you are naming new layers. One of them is that you can't use spaces in layer names. So, for instance, the layer name 'Center Line' is not allowed. However, you can replace the spaces with either a hyphen (-) or an underscore (_). Both of these (-) and (_) are valid layer name characters in Layer naming. So, the layer names 'Center-Line' and 'Center_Line' are both allowable. Now thinking of other special characters, they are absolutely not allowed except for one i.e. dollar sign. The dollar sign is only the other symbol that is allowed after the hyphen and underscore symbols. If you do use a unsuitable character, AutoCAD will make you know about it by displaying the error message box as shown below.

The other limitation relating to layer names is that you cannot use the layer names of more than thirty-one (31) characters. Actually, it is quite rare to provide a layer name that much long, but you need to know that the names can only be between 1 & 31 characters long. By chance if you enter the name of new layer you created longer than thirty-one characters, AutoCAD will automatically display the error message box as shown below.

Layers are always listed in alphabetical order in the layer lists. The only way to control the list order is to manage the naming of layers in a suitable alphabetical order. Remember that providing a layer with suitable name is very important because there may be many different layers in a complicated drawing and it is quite a waste of time to search for the right layer.

How to set color & Linetype 'ByLayer'?

AutoCAD offers 2 ways of setting the color & linetype of drawing objects. Firstly, the color & linetype can be set by 'ByLayer'. The second method is to set the color & linetype by object. In general it's good practice to set color & linetype properties ByLayer because this one is more efficient & less confusing in the long run.

How to set the color of a Layer?

It is quite simple to set the layer color when the layer is created, and it can be done whenever you want. You can change the layer color as many times as you desire.

In order to set the layer color, open "Layer & Linetype Properties" dialog box, click on & then click on the color icon listed in the layer list. You can see that all the layers have their individual color icon & each of them change to display the layer color. You can select the color you want either by picking on the color palette or you can enter the color name or no. in the text edit box.

When you have finished selecting the color you want, hit on the 'OK' button in order to set the color. AutoCAD uses 225 colors along with the drawing background color, irrespective of the abilities of your video display.

Providing various colors to the layers you created will make easier to work with the complicated drawings. It enables you to visualize & differentiate all the drawings very clearly.

How to set the Linetype of a Layer?

You can also provide a Linetype to a layer in the same way you assigned a color to a layer. For instance, you may have all the lines on a layer as 'Hidden' display in a green dashed line. In order to set a linetype to a layer, choose & then click on the layer you created to change the linetype. All newly created layers have 'Continuous' linetype by default. You can change the name by clicking on the linetype name, it brings up the 'Select Linetype' dialog box as shown below.

As you can see in the dialog box there is only one linetype i.e. Continuous. This is because all other linetypes are stored in an external file & you have to load them before you use them.

How to load the Linetypes?

In order to load linetypes, click on 'Load..' button in the dialog box shown above. The 'Load or Reload Linetypes' dialog box will appear & is displays all the list of available linetypes.

You can select as many linetypes as you want & then press 'OK' button to return to the 'Select LInetype' dialog box. You can use 'Ctrl' key to hold down making multiple selections of linetypes and then load all of them in one go.

After returning to the 'Select Linetype' dialog box, the linetypes you selected are displayed in this dialog box list as shown above. Now you can assign one of the linetype to a layer, simply by clicking on the name & then press 'OK' button.

5.3 Creating and Inserting Blocks

Blocks are drawings that can be inserted, scaled, & rotated into another drawing & used again & again within a single drawing or inserted into multiple drawings. They form the basis of the creation of a symbol library.

Basically, there are two types of blocks to use. BLOCK is a drawing (or symbol) which can only be used repetitively within the current drawing. And, a WBLOCK is symbol that is created & stored permanently in a separate drawing file. WBLOCK(i.e. Write BLOCK) operates globally and can be used repetitively in any drawing.

Creating BLOCK:

Click the MakeBlock icon.

or

Type BMAKE in the command line

Command: BMAKE or BLOCK

Type the name of the block.

Pick an insertion point.

Select objects to be included in the block definition.

click OK.

Inserting BLOCK:

Type INSERT in the command line

Command: INSERT

Choose the name to insert a local block and browse to insert a Wblock.

Choose the insertion point, scale and rotation of the block.