So I have this part, or should I say future group of parts that I am going to need to flatten, detail and cut on my plasma table. I have the parts put together to create the 90° slot shaped ducting but for the life of me I cannot get the large diameter to convert, flatten, or anything useful. So here are my parts for anyone to help out. Also, the 90° slot shaped ducting is going to be mirrored at the right plane.

Solidworks 2015 SP2.1 x64

Dell Precision T5810

NVIDIA Quadro K620

Please help or point me to a resource that can help. Thank you