NX Visible edges are not shown on a view since they are rendered as Hidden Line.

Specific components have missing lines in drawing views (without interfering solids).

 
The missing lines are actually unintended handled as Hidden Lines, and may 
occur again in following situation:

1. Orient the model differently in the view or 
2. Suppress a component in front of the problem area.

Solution

The root cause was the quality of a (un-parameterized) solid in a component. 
This component was in front of the area where the lines are missing.


A) Solution for the root cause: 

1. Running Optimize Face on the culprit solid (orange in picture), in order to improve the quality of the solid.
   
   
   
   

B) Other ways to fix this is via the View Settings > Common > Configuration: 

1. Change tolerance to more tight value e.g. from 0.05 to 0.025 (leave as Exact view) 
2. Change representation form Exact view to Smart Lightweight. (no need to edit tolerance)

Notes and References

Hardware/Software Configuration

Platform: INTL64
OS: window
OS Version: 1064
Product: NX
Application: DRAFTING
Version: V11.0
Function: DRAWING/VIEW

Ref: 001-8994217