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    By Dennis Collin

    When plotting in AutoCAD it is very useful to control the output for different kinds of drawings. This control is applied by using a function called a Colour Table, referred commonly as a CTB file. This option can be located within both the page setup command, the plot command and export to DWF and PDF options.


    Fig 1. CTB files controlling plotting output. Colour, Greyscale and Monochrome

    Colour drawings can be useful to show different service routes and for space planning. Grayscale options are good to show a building underlay with services in a high contrast colour. However, for most drawings a simple monochrome style is applied to the plot instead. It is also possible to create a hybrid CTB for specific bespoke documents.


    Fig 2. The plot command with the most commonly used CTB files highlighted.

    The method of controlling the plot style is defined within the AutoCAD template. So, if a CTB function is desired it is important to use the correct template at the outset of any AutoCAD setup.

    When starting out it is usual within the UK to apply a metric template ‘acadiso.dwt’ - this can be found on the main start tab in modern AutoCAD versions. ‘acad.dwt’ should be avoided unless there is a requirement to draw in inches. The wrong choice here can cause all kinds of problems with linetype display, scaling issues and lost time!


    Fig 3. Choosing the correct AutoCAD template is vital

    This acadiso template can be developed with the addition of layers, styles, setups and layouts and then saved with your company name to be the start file of all newly created drawings from your organisation.

    If, however a template such as the ‘acadISO -Named Plot Styles’ is used this will set AutoCAD to use a more advanced and complex plot setup. This method is useful if such colour standards as Pantone, RAL or Truecolour are required. This is unlikely for most companies that just need to deliver standard technical drawings containing notes, measurements and simple colour fills. However, the selection of this template will create plotting problems as all the normal plotting CTB options will be missing!

    This problem can also happen when you are in receipt of other consultant drawings. In this case the drawing creation process was outside of your control.  The symptom of the problem is highlighted in the image below, where there are only STB files listed, not the expected CTB files making a desired output difficult.


    Fig 4. Choosing the wrong template, means that expected CTB settings are missing!

    This problem can be easily fixed. Simply copy the problem drawing into a new CTB based clean drawing, or alternatively, a much easier method is to use the CONVERTPSTYLES command.

    This will convert the Named Plot Styles (STB method of plotting) to the more conventional and expected CTB method.


    Just type in CONVERTPSTYLES on the command prompt, press enter and a dialogue will appear requesting confirmation.  Simply click OK and then plot as normal, setting CTB options and page setups as desired.