>>Otherwise if you do want to make it in MoI you would instead need to use some surface modeling tools to build it, something like trim >>away some areas and then build a sweep in there instead of trying to use fillet. Let me know if you want to try that and I will try to >>help you with it, but really if you have another solid modeling system available to you, it's easiest to export over to it and do the fillet >>there.

As someone who has encountered similar problems with the fillet function, I can highly recommend using the "sweep" function. In many ways, you get better control over the final shape and how it relates to the various surfaces.

Give it a try instead of expecting a one click solution!

Cheers,

Chris