When Grasshopper region difference does not work

Region difference doesn’t work properly while working with Grasshopper.
I know that region difference only applies to closed curves, so I tried making all the curves closed, but that doesn’t work either.
How should i solve this?
The group of light green areas in the file is where I got stuck.
Uploading: Site Modeling.gh…
Uploading: 서울대입구역.3dm…
The work I am currently working on is urban modeling, and the blocked bobbin is the part that disappears when the crosswalk area meets the road boundary.

Welcome @lee_taeyang Can you upload your files again as they seem to have gotten stuck in the upload process

Site Modeling.gh (101.5 KB)

서울대입구역.3dm (221.4 KB)

It’s my first time uploading, so I didn’t know if the upload was cancelled.

File re-uploaded!

You should include the relevant data (internalize geometry) and if possible avoid plugins that are not relevant to the problem. When I open your file I need the AtIt plugin, but even then there is data missing from your harddrive (a .shp file)

SITE.3dm (713.8 KB)

This is a file that does not appear in the plug-in related to the hard disk file.

I noticed in your region difference, you need to define the plane in order for it to work. EditL forgot to mention you also need to flatten your B input:

Thank you, I’ve been trying and searching all day today, and now I’ve solved it