Welcome to CADVANTAGE’s No Nonsense, Quick Start, Step by Step tutorial for Linetypes and Hatch patterns.

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Linetypes and Hatch Patterns


Step 1

What is a Linetype file ?

AutoCAD Linetype file is an ASCII file with extension .lin

The files are created using a text editor like notepad.

AutoCAD can read linetype definitions directly from these files and lay them out on the screen in the form of dash and dots.



Linetypes are defined as series of repeating set of dash, dots and spaces.

Step 2

What goes inside a Linetype file ?

Numbers representing the various dash and dots, plus the amount of space between them, are elements of a linetype definition.

Linetypes that come preloaded with AutoCAD are stored in the file ACAD.lin which sits in the support folder and should always remain there.

New linetypes that you may define, can be directly stored in the ACAD.lin file or a seperate file with an extension .lin




.
Step 3

We will use Notepad to write the linetype file.

Click the Start button and select Run.
Step 4

A dilaog box will appear.

Type notepad.

Click OK or press Enter at the keyboard.

Step 5

The general procedure for linetypes will be:

  • Write the linetype description file using notepad.
  • Save the file with a .lin extension.
  • Load the .lin file using the linetype command.
  • Assign the newly defined linetype to AutoCAD objects.

    • Step 6

    As shown in figure on the right, the shape file consists of two parts :

  • The Header part on line 1
  • The Numerical Description part on the next line.

    • Step 7

    In the header part, * signals the begining of a linetype in file followed by the linetype name which will appear in the linetype dialog box in AutocAD.

    This is followed by a comma and after that, a short visual description of the linetype is written using dash, dots and space.

    This description will also appear in the linetype dialog box in AutoCAD and helps the user visually when selecting a linetype to load and assign.


    .
    Step 8

    As discussed in Step 2, a linetype file consists of dash and dots.

    To define a linetype called MYFIRST with a small dash and a dot followed by a big dash and a dot, as shown in figure, follow these steps:

  • Type the header line as shown in figure.
  • Put the dashes with the underscore and the dots with period.
  • On the next line, type an A as a rule, followed by a comma.
  • The first element .5 is for the small dash.
  • The next -.5 ie. the negative number is for the space.
  • Zero means a dot.
  • Press Enter at the keyboard after typing all the numbers.
  • Save the file as MyLinetypes.lin.
  • Switch to AutoCAD and type linetype at the Command: prompt as shown in figure.
  • In the Linetype Manager dialog box, click the Load button as shown in figure.
  • In the Load or Reload Linetypes dialog box, click the File... button as shown in figure and select the MyLinetypes.lin file.
  • If there are no errors, the name of the linetype - MYFIRST and the description you typed will appear.
  • Select the linetype and OK your way out to the drawing editor.
  • Have fun !


    • Positive number is a dash
    Negative number is a space
    zero means a dot





    Step 9

    Hatch patterns are a combination of linetypes arranged at some angles to each other.

    Hatch pattern file is an ASCII file with extension .pat

    AutoCAD stores definitions in the standard ACAD.pat file which can be found in the AutoCAD support folder and should always remain there.

    The header part of a pattern definition consists of an asterisk (*) and Pattern name followed by a comma and then the description of the pattern as shown in figure.


    Step 10

    When a hatch pattern is constructed, AutoCAD first draws a linetype, then copies the line parallel to itself at a distance you specify.

    It contitues to copy parallel lines until the area to hatch is filled.

    When defining a hatch pattern, you must specify these distances and angles in a very rigid format and we will discuss these in the following steps.


    .

    Step 11

    The first 5 elements of the numerical description part of a pattern follow a rigid structure.

    To create the Angle pattern as shown in figure, we have to define two linetypes each on one line.

    The linetypes are perpendicular to each other and when combined together, they will form the Angle hatch pattern as shown in figure on the right.

    Step 12

    In the description part, the first element is the angle at which the linetype is to be drawn.

    As shown in figure in the last step, the first linetype ie. the horizontal linetype is at angle zero, so the first element is 0

    The second and third elements are the origin for the linetype which is 0,0.

    In AutoCAD, all linetypes of a hatch pattern are drawn beginning at 0,0 but they are hatched only inside the user specified area as shown in figure.




    .

    Step 13

    The fourth element is the offset value.

    By providing a a non-zero offset value, the linetypes are moved ahead by an amount of offset value every time they are copied parallel to each other.

    This is illustrated in figure on the right.

    In case of the Angle hatch pattern, the offset value is 0, so the dashes in the linetypes stack up exactly above each other for the horizontal lines and lay eaxctly besides each other for the vertical lines.

    They are also seperated by a parallel distance specified by the fifth element and explained in next step.


    With offset value of 1, dashes move ahead when lines are copied parallel to each other.



    With offset value of 0, dashes stack up exactly one above other.

    Step 14

    The fifth element is the distance between parallel lines as shown in figure.

    For the Angle hatch pattern, the distance between parallel lines is .275

    This completes the 5 mandatory elements which are followed by the actual linetype definition.

    The first element in actual description is .2 for the first dash followed by a negative number -.075 which is for the space.

    Similarly, the decription elements for the vertical linetype will begin on a new line and the line will be oriented at 90 degrees.


    The fifth element for the Angle hatch pattern is .275


    Step 15

    The combination of these two lines will produce the Angle hatch pattern.

    After the description for the second line is complete, press Enter at the keyboard for a carraige return.

    This is done because a hatch pattern definition file should not end with the cursor on a line with characters.

    You may want to use a newly created hatch pattern in AutoCAD. To do this, copy the header and all description element lines and paste them to the end of the ACAD.lin file that sits in the Support folder of AutoCAD and must always remain there.

    When you use the AutoCAD BHatch command, the hatch pattern will be listed as the last item.

    Caution - Do not add the Angle hatch pattern definition to the ACAD.lin file as it already exists there.

    Add only new definitions that you might create and give it a unique name in the ACAD.lin file.
    Step 16

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