Plotting to scale

Original Article Date:  July 16, 2001

Read this and learn how to set up your MicroStation V7 plot scales, fine tune your paper sizes and deal with plotting a metric file even if your plot driver is in imperial units!

Getting Started…the Plot Dialog Box:
The first step in plotting with MicroStation is determining what you want plotted – either the contents of the a view, or the contents of a fence. Defining your plot area with a fence is preferable since it allows the user greater control over specifying the plot area.

The following options are available:

• File > Print/Plot to open the Plot dialog box

• Entity > Fence to instruct MicroStation to use an existing Fence for defining the plot area.

• Setup > Page to open the Setup dialog in order to select the desired sheet size. The sheet size will automatically default to the last size record in the PLT file being used. In most cases it will be ‘E' for imperial and ‘A0' for metric.

• Rotate 90° on/off to specify if the plot is to be rotated. MicroStation rotates the drawing on the sheet. To rotate the sheet on the plotter, reverse the size records in the PLT file. For instance (35,23) will become (23,35).

• Setup > Layout to open the Plot Layout dialog box. This dialog allows you to adjust the margins, the plot height and plot scale. By default MicroStation will maximize the size of the plot on the selected sheet. Alternatively, a plot scale can be entered via the two following options:

• Scale to <___> % of normal indicates the percentage of the sheet the plot will use. This number will vary depending upon the plot size and the page size defined in the PLT file.

• Scale to <__> MU:SU/IN allows you to enter the scale of the plot by keying in a plot factor. The plot factor is simply the number of working units to plot per inch of paper (or per mm of paper). For example if the imperial working units are Feet/Inches and you want an output scale of 1” = 5' then the plot factor would be 5. This would result in 5' in the design file being plotted on 1” of paper. The default value in this field is the maximum scale that will fit on the selected sheet size.

  Using a Metric Design File and Imperial Plotter Units:
  If your design file is set up in metric (1m:100cm:10) or (1m:1000mm:1pu) and an imperial plot driver file is being used, a conversion factor must be calculated. We know that there are 2.54 cm/inch which is the same as 25.4mm/inch or 0.0254m/inch.
  
  Knowing that at a scale of 1:1 - 0.0254 meters in the file will equal one inch on the plotter, we can simply multiply our output drawing by 0.0254m/inch in order to determine the plot factor:

  Output Scale

  Plot Factor

  
  

  1 : 100

  2.540 m / inch

  
  

  1 : 50	1.270 m / inch
  1 : 25	0.635 m / inch

  
  
  The resulting plot factor will be entered in the Scale to <__> MU:SU/IN field in the Plot Layout dialog.
  
  When Measuring:
• To determine how large an element will be once plotted, use the following formula:
  Meters in the file / Plot factor = Inches on the plotter
  For example: How big will a 16.5 meter line be if sent to the plotter at a scale of 1:100? 16.5m / 2.540m/in = 6.4960 inches

• To determine how large an element will be in the file:
  Inches on the plotter x Plot factor = Meters in the file
  For example, on a 1:50 plot, how big will a 9 inch line be in the file? 9in x 1.27m/in = 11.43 meters

Fine-Tuning Sheet Sizes:
The size records in the plot driver files are typically adequate, however they can be easily modified to suit your plotting requirements. The typical size record appears as the following in the plot driver file:
size=(17.0,22.0)/num=0/off=(0.27,0.27)/name=c

• size=(17.0,22.0) indicates the sheet size and controls which sheet sizes are displayed in the Setup dialog. This size of the sheet should not exceed the maximum printable area of your printer/plotter.

• num=0 is for multiple tray printers and determines the page size number. For printers/plotters where no page size number is required, the default is zero.

• off=(0.27,0.27) controls the location of your plot within the maximum printable area by defining the distance from the plotter origin and to where MicroStation will begin plotting. If the values are set to (0.0,0.0) the plotter will start plotting at it’s margins which is the closest you’ll be able to plot to the edge of the paper. It will also allow you to determine the origin of the plotter.

• name=c controls the ‘name’ of the sheet size which is displayed in the Plot dialog. For certain types of plotters the name must be set according to the specifications determined by the manufacturer. For instance, on HP plotters where sheets are longer than 50 inches the name must be set to LONG_AXIS

The Maximum Printable Area:
All plotters have physical/mechanical limitations which restricts the plotters ability to utilize the entire width or length of a sheet. The area that the plotter can plot to is commonly referred to as the “maximum printable area” or “hard clip limits”.

MAXIMUM PRINTABLE AREA = PAGE SIZE PLOTTER MARGINS

By knowing the maximum printable area of your plotter, you’ll be able to set up your paper sizes to avoid the problem of “clipped plots”.

Plotter Page Setup:
To set up your sheet border in MicroStation and determine your size records in the PLT file, use the following:

sheet height - (top margin + bottom margin) = height for size records
sheet width - (left margin + right margin) = width for size records

For example, for a 24" x 36" sheet with a 1 1/2" left margin and 1/2" margins around the top, bottom and right sides of the sheet, the calculations would be:

24" - ( 1/2" + 1/2") = 23" (height)
36" - (1 1/2" + 1/2") = 34" (width)

• Open the plot driver configuration file with a text editor.

• Scroll down until you see the following line:
  size=(22.0,34.0)/num=0/off=(0.27,0.27)/name=d

• Replace the sheet sizes with the calculated values:
  size=(23.0,34.0)/num=0/off=(0.27,0.27)/name=d

• Determine the offsets by using the following equation:
  (desired margin) - (plotter margin) = (offset)

Recall that the offsets are the distances from the plotter origin to where MicroStation starts plotting.

If you are not sure of your plotter's origin, fence and plot a small rectangle (5" x 5") to a large sheet. The corner of the rectangle closest to the corner of the paper is the plotter origin.

Metric Plotting:
To plot in metric units, use the metric size records and resolutions in the plot driver file:

; Metric size records
; size=(158,244)/num=0/off=(0,7)/name=a4
; size=(229.0,355.0)/num=0/off=(0,7)/name=a3
; size=(355.0,508)/num=0/off=(0,7)/name=a2
; size=(788,508)/num=0/off=(7,7)/name=a1
; size=(1066,813)/num=0/off=(7,7)/name=a0
; resolution(MM)=(0.025,0.025)

By default these records are commented out with a semi-colon and are set to millimeters. Meters can be used as the unit by simply moving the decimal point of the sizes 3 spaces to the left. Remove the semi-colon on these records, and then add semi-colons to the imperial records.

Note that if you’re using PRINTER.PLT (the system printer), the Metric/English setting is controlled in the Control Panel under Regional Settings in Windows.

Using a Metric Design File and Metric Plotter Units:
To calculate the plot factor, you need to specify the number of master units (m) in the file to be plotted per mm paper. For example:

1: 5,000 means that 1mm on the plot represents 5,000mm on the ground. Thus to calculate the plot factor use the following cartographic scale formula where:

Scale Factor = Map Distance / Ground Distance
Plot Scale = Scale Factor x (Master Unit / Plotter Units)

For example: The plot factor for a 1:5000 is calculated by:
5000 x (1m/1000mm)= 5

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