I'm not very proficient with Civil 3d because I don't get the opportunity to use it often. I created two feature lines that form a rough rectangle. I created two grading groups to grade to my finished elevation. One feature line has a 3:1 slope, the other 4:1. I was able to grade the first line, but every time I try to grade the second, C3D freezes. I'm not sure if it's because I'm doing something wrong/not best practice/etc, or if my computer doesn't have enough "power".
Win 7 Pro, SP1 64 bit
Intel Core i5-3470 CPU @ 3.2 GHz
8 GB RAM
Civil 3D 2018
File located here: https://www.dropbox.com/s/h2tz0b3ugf...018.1.dwg?dl=0