Adding a Custom Hatch Pattern to AutoCAD 2019

By James Philip 

I was asked recently to create a Flemish bond hatch pattern and my immediate response was that if you search the internet you will find one that already exists and I did. See Fig 1

Fig 1

Specific brick sizes were then requested, so I replied that you can just edit the file to represent the brick size you require. Below is an explanation of how I did it.

The file that I found had brick sizes of 215 x 65 and 102.5 x 65 and a 10mm mortar thickness. To edit the *.pat, you open it in Notepad. The file looks like this.

*HBFLEMET,Brickworkflemishbond Free patterns from http://www.cadhatch.com/

0,0,10,0,150,215,-122.5

0,0,75,0,150,215,-122.5

0,225,10,0,150,102.5,-235

0,225,75,0,150,102.5,-235

90,0,10,150,337.5,65,-85

90,215,10,150,337.5,65,-85

90,225,10,150,337.5,65,-85

90,327.5,10,150,337.5,65,-85

0,168.8,85,0,150,215,-122.5

0,168.8,150,0,150,215,-122.5

90,168.8,85,150,337.5,65,-85

90,46.3,85,150,337.5,65,-85

0,56.3,85,0,150,102.5,-235

0,56.3,150,0,150,102.5,-235

90,56.3,85,150,337.5,65,-85

90,158.8,85,150,337.5,65,-85

Each line of code represents a line in the hatch pattern. To fully understand this I have illustrated each character set.  See Fig 2

Fig 2

To understand and verify the offset distances you can create a dimensioned layout of the existing hatch pattern. See Fig 3

Fig 3

My new hatch pattern required brick sizes of 240 x 50 and 115 x 50 and a mortar thickness of 15mm. The resulting dimensioned layout is as follows. See Fig 4

Fig 4

The edited *.pat file then looks like this

*JP,Brickworkflemishbond

0,0,15,0,130,240,-145

0,0,65,0,130,240,-145

0,255,15,0,130,115,-270

0,255,65,0,130,115,-270

90,0,15,130,385,50,-80

90,240,15,130,385,50,-80

90,255,15,130,385,50,-80

90,370,15,130,385,50,-80

0,192.5,80,0,130,240,-145

0,192.5,130,0,130,240,-145

90,192.5,80,130,385,50,-80

90,47.5,80,130,385,50,-80

0,62.5,80,0,130,115,-270

0,62.5,130,0,130,115,-270

90,62.5,80,130,385,50,-80

90,177.5,80,130,385,50,-80

This should be saved to its own *.pat file (e.g. Flembond.pat) and placed in the support folder where the acad.pat and acadiso.pat are located.

Do not edit these files (acad.pat or acadiso.pat) and add the code to them. Creating the patterns in separate files ensures that if the software is re-installed these files are not over written.