Appendix D Custom Linetypes and Hatch Patterns This appendix will outline the basic procedures for creating custom linetypes and hatch patterns if you need something that isn't found in AutoCAD itself or with any third party vendor. All linetypes and hatch patterns were originally "coded" by hand and there is nothing inherently special or magical about making them; they just take some time and patience to create. Though it's admittedly rare for a designer to need something that isn't already available, creating these entities is a good skill to acquire. We will just present the basics here and you can certainly do additional research and come up with some fancy designs and patterns. Linetype Definitions (Basic) All linetypes in AutoCAD (about 38 standard ones to be precise) reside in the acad.lin or the acadiso.lin file. These are Linetype Definition Files that AutoCAD accesses when you tell it to load linetypes into a drawing. In AutoCAD 2008 these files can be found in the Program Files\AutoCAD 2008\backup folder. Anything you do to these files including adding to them immediately shows up next time you use linetypes. Our goal here will be to open up the acad.lin file, analyze how linetypes are defined and then make our own. Locate and open (usually with Notepad) the acad.lin file and take a look at it closely. Here is a reproduction of the first 6 linetype definitions Border (Standard, 2 and X2) and Center (Standard, 2 and X2). *BORDER,Border __ __ . __ __ . __ __ . __ __ . __ __ . A,.5,-.25,.5,-.25,0,-.25 *BORDER2,Border (.5x) __.__.__.__.__.__.__.__.__.__.__. A,.25,-.125,.25,-.125,0,-.125 *BORDERX2,Border (2x) ____ ____ . ____ ____ . ___ A,1.0,-.5,1.0,-.5,0,-.5 *CENTER,Center ____ _ ____ _ ____ _ ____ _ ____ _ ____ A,1.25,-.25,.25,-.25 *CENTER2,Center (.5x) ___ _ ___ _ ___ _ ___ _ ___ _ ___ A,.75,-.125,.125,-.125 *CENTERX2,Center (2x) ________ __ ________ __ _____ A,2.5,-.5,.5,-.5 Let's take just one linetype and look at it closer. Here's the standard size center line: *CENTER,Center ____ _ ____ _ ____ _ ____ _ ____ _ ____ A,1.25,-.25,.25,-.25 The two lines that you are seeing are the header line and the pattern line; both are needed to properly define a linetype. The header line consists of an asterisk, followed by the name of the linetype (CENTER), then a comma and finally the description of the linetype (Center). In this case they are one and the same. 474 | P a g e