patterns.ssi

Function Name:

PATTERNS.SSI

The patterns.ssi file is used to store the pattern definitions that you can use as fill attributes in plotting. It is usually located in the SSI_PLOTTING: directory but can stored and named according to the patterns file specifier as described in the previous defaults.ssi section.

The patterns.ssi file contains pattern definitions formatted as follows:

The first line of each pattern definition begins with the * character and contains two fields delimited by commas. The first field is the pattern name which is limited to 16 characters in length, and the second field is a description of the pattern.
The first line is followed by no more than 30 lines describing the pattern to be plotted. Each pattern line must define an angle, xorigin, yorigin, xoffset, and yoffset. The pattern line may also contain up to six dash specifiers entered at the end of the pattern line.

Lines beginning with the # character are ignored and are treated as comments. All dimensions are typically expressed in centimetres but are really unitless since a scale factor must be defined when the entity fill attributes are defined in the PLOTTING module, in order to give the correct size of the pattern.

Following is a description of the various specifications that can be used in a pattern file.

angle

Angle is the orientation of the line to be drawn, with valid values between 0 and 360. A value of 0 is a horizontal line, 90 is a vertical line going up the page, and 270 is a vertical line going down the page.

xorigin & yorigin

Together these define the start of the position of this line in the pattern. Start positions are generally around the 0,0 coordinates. The pattern is displaced to the required position when used by the plotting module.

xoffset & yoffset

Together these define the displacement, in directions yoffset relative to the hatch line itself, to the start position of the next parallel line segment in the hatch pattern. The xoffset is the displacement along the hatch line. The yoffset is the displacement perpendicular to the hatch line, i.e. the spacing between the hatch lines.

dash(n)

These dash values define the pattern to be used for the hatch line. Positive values indicate the length of the line segment which is to be drawn. Negative values indicate the length of the line segment which is to be left blank. The sum of all the dash lengths, disregarding the sign, defines the pattern repeat length. No dashes is valid and indicates that a solid line will be drawn. Xoffset values are meaningless if there is no dash pattern.

line format

The format of a line is angle, xorigin, yorigin, xoffset, yoffset [,dash1 [,dash2 [,dash3 [,dash4 [,dash5,dash6]]]]]]

# An example pattern file
#
*angle,Angle steel
0, 0,0, 0,.275, .2,-.075
90, 0,0, 0,.275, .2,-.075
*ansi31,ANSI Iron, Brick, Stone masonry
45, 0,0, 0,.125
*ansi32,ANSI Steel
45, 0,0, 0,.375
45, .176776695,0, 0,.375

The method used to define patterns is compatible with the method used in AutoCAD, and any AutoCAD compatible pattern file can be incorporated into patterns.ssi for use with GEOVIA programs.