Bring up the Preferences window by selecting menu item ‘Edit’->‘Preferences’.
Two color modes are supported:
1. AutoCAD Colour Index (ACI) 8 bit colour.
2. FLTK Colour Wheel (CW) 24 bit colour. (Or the max supported depth).
Select the colour mode using the ‘ACI - CW’ slider switch at the top right of the Colour prefs tab:
When you click on a colour well, The AutoCAD Colour Index window appears. If the well colour exists in the ACI table, it’s index and RGB value are displayed; if the well colour is not found, the index field will show '-1' and the RGB filed will show '?, ?, ?'. The clicked colour is displayed in the large colour well at the bottom left, whilst the current colour is shown adjacent. If you want to find a colour by its index value alone, click 'Show labels'.
The advantage of using ACI mode when exporting DXF is that Layers are given the same colour index value as the Isolate Group colour so that when you open the file in AutoCAD, the colours match.
Generating Isolate Set Colours
You can set colours for Isolate groups on the ‘Colours’ tab of the ‘Preferences’ window.
Click the ‘GENERATE’ button to generate a new set of random colours, or fine tune the generated set by clicking on the colour wells. There are enough colours for 68 groups, which should be more than enough in most instances. When the number of Isolate groups exceeds 68, a random colour is generated for the element.
When the radio button ‘Use generated colors’ is on, the generated colours will be used for all Isolate sets (Faces, Struts, Hubs, etc). When the radio button ‘Use random each click’ is on, a new array of random colours is generated every time you click an element with the Isolate tool. Isolate Set colours are persistent and saved to the prefs.
When you change Colour Mode, you must regenerate Isolate Set colours so that they conform to the current pallette.