Sometimes I think this topic should be renamed “why does Rhino have lots of issues filleting simple surfaces”? 
Green and blue are tangent. Rhino’s FilletEdge attempts to do this in a single surface and fails. Why can’t it just give up and split it into two surfaces, saving us all from a lot of manual work AND getting cleaner fillet surfaces at the same time?
EDIT: An hour later, sort of similar issue… the crazy thing is that these are not advanced fillets! It’s super simple stuff, and Rhino fails (I had to take the body into a different CAD package, and there it was just one click, as it should be)…
(Oh, and the Y-fillet in the bottom left corner there? That’s also a different CAD package, because of course Rhino couldn’t do that either. I’ve said preciously that I’d pay double the price of Rhino for an unfillet command, and I’ll say the same for actual, good filleting capabilities.)
EDIT: This one was new to me…
