Cadmonkey3D

Hi, I can create threads in Fusion and 3d print the parts good using Cura with our Ulitmaker 5s. When I use Inventor to create the threads and convert it to a .STL file then use the Cura with our Ultimaker 5s, the threads come out wrong. I have included a pic. You can see the shadows of the 2 orange pieces show the threads leaning to the left and not like the top sample straight up and down. Is this a problem with .STL converter in Inventor?

Has anyone used Prusa Slicer with the Ultimaker and have good luck with threads? Currently, I'm using Cura and threads are not coming out correct. Will Prusa work better with Ulimaker? Then software I'm using is Inventor. Thanks, Jeff