I assume that you want certain curves (edges) of a model shown in a Drawing view to have a wider or 'bolder' appearance, correct?
If so, while in the Drawing, go to...
Edit -> View -> View Dependent Edit...
...select the view of interest, and when the dialog becomes active, select the second icon in the 'Add Edits' set of icons labeled 'Edit Entire Objects' and then in the 'Wireframe Edits' section of the dialog change the 'Line Width' to what you want, then hit 'Apply' and then select the curves that you wish to edit and then hit OK a couple of times and you should have what you want.
John R. Baker, P.E.
Product 'Evangelist'
Product Engineering Software
Siemens PLM Software Inc.
Industry Sector
Cypress, CA Siemens PLM: UG/NX Museum:
To an Engineer, the glass is twice as big as it needs to be.
If you want to change all lines of a certain type (visible, hidden, smooth, etc) in a view, you can control this in the view style dialog and edit the line thickness of the desired line type.