AutoLISP Help – Keep Only Outermost Polyline Inside Boundary

[Tamim]

Description:
I have a sample drawing where:

The outer boundary is in red color (closed polyline).

Inside this boundary, there are several cross polylines (in white).

Some of these inside polylines are offsets or overlapping.

My Requirement:

I want to keep only the outermost polyline inside the boundary.

The inner offset/cross polylines should be trimmed or deleted automatically.

The result should leave only the clean outer boundary and remove the unwanted inner lines.

Sample.dwg

[SLW210]

 

 There are some LISPs/programs out there.

 

AutoCAD Architecture FREE toolset has the AECLINEWORKSHRINKWRAP command.  

 

Or... Polyline Outline (Advanced) | Lee Mac Programming.

 

Maybe this... TotalBoundary • Outline creation tool - Programs and Scripts - AutoCAD Forums

 

Maybe something in this thread...