The dimension line color can be modified within the prototypes.
Perform the following steps:
1. Open the prototype file in Advance Steel. The prototype files path is:
C:\Documents and Settings\All Users\Application Data\Graitec\AdvanceSteel\2010\Shared\Support\Prototypes
2. Launch the Change dimension style command.
3. In the Dimension Style Manager window click Modify.
4. Select the Lines tab. Several options are available for changing the dimension line colors or other dimension style parameters.
5. Save the prototype. The changes are available only for drawings using the modified prototype. These changes can also be applied to the current drawing using the same command described above.