Open Roads SS3 Bentley Civil Survey- Is there a way to save the Terrain Model perimeter to an exterior boundary linear feature in Bentley Civil Survey?

Question

I have used the 'Edit Terrain Model' command 'Delete Edge Triangles' to clean up my triangles which changes the shape of my perimeter. If I 'Reactivate Survey Processing Rules' I'll lose my edits and the perimiter will redraw to the original extents. So I want to save the edited perimiter as a linear feature in Survey with a Boundary feature type. The method I'm trying to use is to right mouse click over 'ALL Linear Features' and select 'Add Graphic Linear Feature'. The problem I'm having is when I'm prompted to identify element I get the message "Zero length element not allowed".

Frank Boston · Accepted Answer

For PowerGEOPAK, here's what I've put together as a workflow recommendation for our users, based partially on work in this and related forums. I don't know if something similar would make sense for InROADS, as I don't use it.

Finish editing your source data for your surface (don't edit triangles yet) 
 Right-click on survey project in Project Explorer &ldquo;survey&rdquo; tab, select &ldquo;deactivate survey processing rules&rdquo;. Otherwise, it will show up as &ldquo;not an editable terrain&rdquo;. (Note: either the data is editable, or the terrain is editable. Not both.) 
 Triangles can now be edited. Survey data is NOT live; points cannot be added or moved and have triangles follow the changes. 
 It makes no difference if the terrain model (in the civil model tab of Project Explorer) is locked (rules deactivated) or unlocked (rules activated). 
 IF RULES ARE REACTIVATED in the Project Explorer &ldquo;Survey&rdquo; tab, ALL TRIANGLE EDITS WILL INSTANTLY REVERT. 
 To save a clip boundary to protect the triangle editing along the boundary follow this process. 
 Exit MicroStation and make a copy of the file containing the terrain. 
 Open that copy 
 Select the boundary 
 Activate the &ldquo;drop element&rdquo; tool 
 In the &ldquo;Drop Element&rdquo; dialog, uncheck all boxes except &ldquo;Application Elements&rdquo;. Click a data point to accept. 
 Export this boundary line, using FileFence or something similar 
 Exit this file, re-open your original terrain file 
 Import the new boundary line (ref merge) 
 Select this line 
 Open the survey tab in Project Explorer, right-click on &ldquo;ALL Linear Features&rdquo; under the appropriate field book, and select &ldquo;Add graphic linear feature&rdquo;. 
 Left-click on the line and hold to get to the Properties menu. 
 Change the feature definition to CLIP and the Terrain Model Attribute to &ldquo;Determine by feature definition&rdquo;

RECOMMENDATIONS 
 Note that saving a clip boundary using the method outlined here will ONLY preserve your triangle edits along the boundary of the project. No internal edits will be preserved. Our suggestion is to NEVER edit the internal triangle structure; rather, you should edit the source data to fix any issues, so that the triangles reflect your intent. 
 Don't forget that one of the best advances in SS3 terrain modeling is that ALL functions can be undone. If you do something and your triangle edits revert, stop, take a breath, and UNDO. Now take time to think about what you need to do, and prevent the problem if possible. 
 
 (Note- I posted this previously here: https://communities.bentley.com/products/road___site_design/f/5922/t/98064.aspx )