Taking the RED out of colour tables

Original Article Date:  February 2001

Updated:  August 2010

Learn how MicroStation handles Colour Tables and Color Tables

To control the display of element colours in MicroStation, it uses a Colour Table which is essentially a palette of 255 colours numbered from 0 – 254. Note that colour index 255 is reserved for the background of your design.

There are several methods of attaching a colour table:
(1) Using the key-in CT=colour table name When using this method, MicroStation writes a Type 5 (group data) Element on Level 1. The next time the file is opened it will read this element and display the correct colours. Although the colour table element contains a filename for the “attached” color table -- it does not make a ‘call' to that file since the colour information is stored within the Type 5 Element.

(2) From Settings > Colour Table > Attach. This will attach the colour table shown in the dialog to the active design file. Again, a Type 5 Element is written to the file so that the next time the file is opened the correct colours will appear.

(3) From Workspace > Configuration > Colours > Edit MS_DEFCTBL to the colour table of your choice. This method is sets the Default Colour Table which MicroStation will use on all files except those that have an existing Colour Table Element (Type 5 Level 1). If MS_DEFCTBL isn't defined, then hard-coded internal values are used.

Other key-ins:
CT=$ Returns the message: file = NONE (default is in use) This indicates that the file is using the colour table as defined by MS_DEFCTBL

CT=$ Returns the message: user attached from dialog tells the user that the data from the Type 5 is being displayed.

CT=[space] Will unload the colour table.

Consideration for Reference Files:
By default MicroStation will display the reference file with it's own colour table. If disabled (Workspace > Preferences > Reference File > Use Color Table) MicroStation will ignore any colour table attached to the reference file and will instead display the elements using the colour table of the active design file.

AskInga Article #39