1. Have you checked you're not in a parallel view mode instead of ortho mode? - check in the projection pad (4 heads for the elevations etc. and pick the plan view icon in the centre, then zoom extents, 2. Check clipcube isn't on, 3. Identify the length of the line - it might be thousands of Km (miles) long making the plan so small against the line, if so delete it and zoom extents,
Thanks for replying but something is wrong everything comes up right in the obligue view and the perspective view but any parallel view just get a green dashed line.
The only other thing I can suggest is to do a file/drawing purge and see if it's corrected in the new drawing. Alternatively, copy and paste the info into a new blank drawing and test that.