First, sorry for my bad english, maybe I’m hard to understand.
Thank you for your feedback, I’m glad that this script is useful.
I changed the script to take into consideration the transformation if it not applied.
Are you sure Blender crashes or it just freezes? I can triangulate 155 000 points in 50 seconds without crash on a common machine (xp, 2Go RAM).
For back faces, it seems to me that Blender doesn’t have double sided faces, I’m wrong? I didn’t find any backfacing options in Blender Python API.
Reverse conversion ? Just edit the TIN to delete edges and faces and you get the points cloud, no?
If you work with Autocad I have an interface to use this code directly in ACAD. It’s another python code who deal with COM objects of AutoCad. Let me know if you’re interested.