I’m not sure about whether i’m right or not, but i noticed that the more threads i use in node mesh.ToPolySurface in spring nodes - the more time it take + it can add errors. maybe you can use multiprocessing instead of threads. I’ve read the article about it (in Russian, though. that multithread and multiprocessing is 2 different things.) maybe it can help, i hope it do. Зачем, когда и как использовать multithreading и multiprocessing в Python / Хабр and Python multiprocessing ⚡ - YouTube, although you can read documentation in python 3 about multiprocessing (can’t add a link, cause the new users can’t add more than 2 links at a time)