Color Mapping in DXF/DWG and DGN Export

Basic export exports all graphics as a single colour. For DGN, this is White, which inverts to black on a white background. For DXF/DWG, it will be either Black or White, depending of the value of the BLACKBG option. It BLACKBG is ON, the graphics will be white, otherwise they will be black.

For Advanced export, colours are mapped on export to DXF/DWG or DGN by their RGB values. Where the DRAW RGB value is close to the RGB value of a defined ACI colour, the colour is exported as the ACI colour; otherwise the RGB value is used. In this context, 'close to' is defined as within a radius of 4 in the RGB space.

DRAW colour 10 (White) and colour 15 (Black) both convert to ACI 7 (or White for DGN), which will invert if on the same colour background. DRAW colour 17 (also Black) exports with RGB 0,0,0 and will be black on all backgrounds, while DRAW colour 24 (also White) exports as RGB 255,255,255 will show as White on all backgrounds.

Note:
DRAW and AutoCAD colour names do not match: DRAW Red has an RGB of 189,0,0 while AutoCAD Red is 255,0,0 (which matches DRAW Brightred at index 18). Similarly, AutoCAD Green has RGB 0,255,0 which does not match the DRAW Green (0,189,0). It does match the DRAW unnamed colour at index 20.

Note:
Users can redefine which colour is used for indices 1-16; alternative indices are given. AutoCAD only names the first 7 colors.