So I went to Thingiverse & found an STL model of Ruby's scythe(from RWBY,you guys should go see it.)
I opened BRLCAD and opened it.
Then this popup showed up with a bunch of parameters.
I didn't what they meant so I left it empty.
Then BRLCAD opens and theres nothing there.
So try opening it again.
But this time I gave 1 as the minimum space between 2 vertices
Then the conversion thing opened and it took a while but it converted it.
Then i positioned the scythe and did the raytrace thing.
I saved it as a PNG file and done