How to use ML.Net to define external walls (external lines)?

Question

C++ / C#

Hello colleagues ! I'm new to ML but really want to figure it out! I have a task: to find all external walls (those on which the rain drips) in the building model. I represent the walls as 2d lines with (X,Y) points at the start and end. Also, each wall instance already has an Outer Wall value, incl. she can be trained. I collect everything in a CSV file, and then I don’t understand where to go. Tell me where to look? Which Algorithm to Choose? It turns out that in order to determine each line, I need the Algorithm to determine the line in space relative to other lines ... I don’t really understand where to move. Thanks in advance