Thanks for the recommendation. I don't know about buying another program just for a fillet though. In general how can I know if MoI can handle something versus other programs? What should I look out for?

Also, I have this issue with another fillet:

Image 1- The curves on a Box after I Boolean Differenced a Lofted Solid.



Image 2- A fillet of 1 works.



Image 3- A fillet of 3 works.



Image 4- A fillet of 2 does not work, even though it's between two working values...