Mesh to BRep Conversion

Hi, I am trying to modify a .stl file in Fusion 360 by first importing the stl file and then converting it to BRep. Β I want to split the body in two (along the flat plane) in order to do a 2-color print (I have a dual extruder printer). Β Unfortunately it is a very large model and I am getting an error message saying the stl file contains too many facets, 479,054.Β  Any workaround for this. Β ο»Ώ
22.8 MB

Aloha! Glad to join in.