Beat me to it... I capped off the 2 surfaces to make solids, then did the boolean and fillet.

Guys thanks.

Michael in a previous thread you told me that it was easier for the command to fillet two surfaces instead of edges of joined surfaces. Why is that method not working here?

Hi niko,

> Why is that method not working here?

It's because your wing part is not just a single surface, it is made up of 4 surfaces joined together.

Note that when you select it, the object type indicator (circled in red below) says that it is a "Joined srf", and not just a "Surface" like it would if it was just 1 surface.



And similarly the fuselage is also made up of 2 surfaces joined together.

You could still use surface/surface filleting by breaking things down into individual surfaces by selecting them and running Edit > Separate.

But that surface/surface filleting will usually be something that you would try if the edge-based one is unable to figure things out.

It can be harder to deal with the surface/surface one when there are multiple pieces involved because you may need to do things like trim the fillet pieces manually and stuff like that.

- Michael

Got it thanks.