About-Hatch-Pattern-Definitions-and-Custom-Hatch-Patterns

About Hatch Pattern Definitions and Custom Hatch Patterns

About Hatch Pattern Definitions and Custom Hatch Patterns

Hatch patterns are defined in one or more definition files that have a .pat file extension. You can use the hatch patterns as they are, modify them, or create
your own custom hatch patterns.

Regardless of where a definition is stored, a custom hatch pattern has the same structure.
It has a header line with a name, which begins with an asterisk and is no more than
31 characters long, and an optional description.

*pattern-name, description

a pattern definition also has one or more line descriptors of the following format:

angle, x-origin,y-origin, delta-x,delta-y,dash-1,dash-2, …

The standard hatch pattern ANSI31 looks like:

and is defined as follows:

*ANSI31, ANSI Iron, Brick, Stone masonry
45, 0,0, 0,.125

The pattern name on the first line, *ANSI31, is followed by a description: ANSI Iron, Brick, Stone masonry. This simple pattern definition specifies a line drawn at an angle of 45 degrees,
the first line of the family of hatch lines is to pass through the drawing origin
(0,0), and that the spacing between hatch lines of the family is to be 0.125 drawing
units.

Hatch pattern definitions follow these rules:

  • Each line in a pattern definition can contain up to 80 characters. You can include
    letters, numbers, and the special characters underline (_), hyphen (-), and dollar
    sign ($). However, you must begin a pattern definition with a letter or number, not
    a special character.
  • Blank lines and text to the right of a semicolon are ignored.
  • Each pattern line is considered to be the first member of a line family, created by
    applying the delta offsets in both directions to generate an infinite family of parallel
    lines.
  • The delta-x value indicates the displacement between members of the family in the direction of
    the line. It is used only for dashed lines.
  • The delta-y value indicates the spacing between members of the family; that is, it is measured
    perpendicular to the lines.
  • A line is considered to be of infinite length. A dash pattern is superimposed on the
    line.
NOTE:A blank line must be placed after the last hatch pattern definition in a PAT file.
If a blank line is not placed after the last hatch pattern definition, the last hatch
pattern definition will not be accessible when using the hatch pattern file.

The process of hatching consists of expanding each line in the pattern definition
to its infinite family of parallel lines. All selected objects are checked for intersections
with any of these lines; any intersections cause the hatch lines to be turned on and
off as governed by the hatching style. Each family of hatch lines is generated parallel
to an initial line with an absolute origin to guarantee proper alignment.

If you create a very dense hatch pattern, the program may reject the hatch and display
a message indicating that the hatch scale is too small or its dash length too short.
Change the maximum number of hatch lines by setting the MaxHatch environment variable
to a whole number between 00 and 10000000 (ten million):

  • In AutoCAD LT, use SETENV and enter a valid number.
  • In non-LT products, use the AutoLISP expression (setenv “MaxHatch” “n“) where n is a valid number.
NOTE:In either case, when changing the value of MaxHatch, you must enter MaxHatch with the capitalization as shown.

Learning AutoCad

sp>Hatch patterns are defined in one or more definition files that have a .pat file extension. You can use the hatch patterns as they are, modify them, or create your own custom hatch patterns. Regardless of where a definition is stored, a custom hatch pattern has the same structure.Hatch patterns are defined in one or more definition files that have a .pat file extension. You can use the hatch patterns as they are, modify them, or create your own custom hatch patterns. Regardless of where a definition is stored, a custom hatch pattern has the same structure.hatch patterns is provided with the product that can be used as they are or modified to suit your needs. You can also create your own …hatch patterns, you can also create … Creating custom hatch patternsHatchpattern definitions have a few rules:.Custom hatch patterns can be very helpful in applying repetitive patterns to an area of a drawing. … (asterisk): Denotes beginning of a new pattern definition.… Read how you can use your own AutoCAD pattern/hatch. … If you use hatch dialog box, you can change pattern type to custom or user defined.Custom hatch creation … The more imprecise the hatch pattern definition, the faster the degradation. … Rescaling hatch patterns for Revit requires extra care to ensure all pattern elements have repetition lengths within the limits for that pattern …hatch pattern definition is stored in a simple ASCII text file with an extension of PAT. You can append a hatch pattern to an existing file if you wish, or you can …custom hatch pattern. … However, if you look up Help – hatch patterns – create…you'll get an idea. … current linetype with the User Defined Pattern option of the Hatch and Gradient dialog box, …… The format for defining the hatch files (.pat) is so bizarre that it almost …. Labels: Autocad, custom, define, file, Hatch, help, pat, pattern, Revit …