Colours in MicroStation

There are two primary concerns with colour control in MicroStation:

• For production drawings it is imperative that linework displays and prints black. Whilst this used to be accomplished simply by sending to a monochrome printer it is increasingly common for spot colour to be used making control over black printing more critical.
• Consistent use of colour for presentation or diagrammatic purposes.

Controlling colour in MicroStation can be open to error. The first thing to understand is that setting colour by using the 0-254 index colours is completely reliant upon the correct colour table being available. MicroStation's default colour table is not of much use for presentation colouring having a limited range of colours:

Other tables can be loaded and it was common for custom colour tables to be created that provided a wider range of more subtle colours. However if the appropriate custom table is not available a carefully established colour scheme will be lost. Additionally, editing these colour tables is a painful task.

• However it is generally reliable for index colour 0 to be white/black (display/print).

Additional complexity can also be introduced when referenced colours are involved leading to unexpected colours appearing in sheets or other output files. Whilst inappropriate colours from references can be overridden in the active, file this is tedious, can be very time consuming and generates inconsistencies that will cause problems later.

If colours are consistently applied at all levels last minute adjustments can be largely avoided.

See Site Standards - Colour Tables for useful advice regarding control of colour tables.

Application

A suggested colour method is set up as follows:

• Set ByLevel colours using index colour numbers 1-30 as above.
• Set appropriate overrides for every level in both site and project level libraries
• Set configuration at site level to synchronise appropriate attributes with the level libraries at file open.
  [Note that this synchronisation is not set as a default in MicroStation's configuration. When introduced to an existing system as the colours used in existing projects could be disrupted so approach with care. One approach to this is to apply synchronisation configuration variables per project for new projects, leaving the site defaults alone for existing projects.]
• Use Colour Books to provide consistent sets of named RGB colours.

Many level libraries are set up with this method in mind so in Level Manager, with Symbology set to Overrides, you will see most levels set to colour 0 to print in black, except for levels where the override is left open for colour fills to print as applied to the elements on those levels:

 
ByLevel vs Overrides Attributes.

Every level has the following ByLevel attributes:

• Colour
• Style
• Weight

Optionally a material can be attached ByLevel and some custom line style settings can be applied ByLevel but these are generally special cases.

ByLevel symbology

The purpose of ByLevel symbology is primarily to control the display of elements on screen during design creation/editing, colour being the most used attribute to visually distinguish levels from one another. The colours used for ByLevel symbology are not important and can be assigned randomly or if preferred chosen to highlight particular levels. It is best to avoid the use of some less distinct colours for heavily used levels.

Override symbology

Override symbology is used to apply consistent attributes, primarily colour, to all elements for printing or on screen presentation. Generally most levels are set with an override colour 0 to print black (and to display black in sheet models where the background is white). Style and Weight are left open so they can be set appropriately by element.

Levels for used for presentation purposes, area fills, etc., are left with all overrides open so that colours can also be applied per element, preferably using Colour Books .

Results

If this approach is followed consistently to all files in a project then one can reliably expect output to be consistent with no surprising splashes of colour.

When DGN files are exported to other formats the elements retain their RGB colours so are consistently transmitted downstream.

Referencing

There are often issues with colours in reference files varying that require manual overriding in sheet files. Use of consistent colours following the method above for all files in a project can at reduce or perhaps even eliminate such issues.