Hi niko, I untrimmed everything, and moved the small one a little tiny bit to the left (so it wasn't just barely grazing the edge of the main piece) and used surface/surface fillet.

- Michael

Hi niko, here is the file before filleting.

You don't need to try and trim and join the pieces beforehand for surface/surface fillet, just have the 2 surfaces as separate objects and select them and run Fillet.

- Michael

Wow thanks

I was under the impression that surfaces had to be joined and you then fillet the edge. that is much easier...

Which brings me to the next question


I guess the rules of filetting is a dark cloud to me.
How come I can't fillet a cube intersecting a sphere the same way you did the last two surfaces??
Sorry for being a dumbass man I just want to learn everything I can about MOI..

Hi niko, Michael did mention 'surface to surface', so if have a sphere intersecting a cube both are solids and that method of filleting won't work for that situation, but if you separate the cube into individual surfaces you can then use surface to surface filleting and then join everything back to a single solid body.
Usually in that situation you would Boolean union the solid bodies then apply the fillet using the intersecting edge, either way works.

Cheers
Danny

Hi niko,

> How come I can't fillet a cube intersecting a sphere the
> same way you did the last two surfaces??

Well, you could, but like Danny mentions you would need to break the cube up into individual surfaces.

That other kind of fillet is a surface modeling technique that builds a fillet between just 2 surfaces.

If something is made up of a lot of surfaces and also has sharp corners where those surfaces meet, then the regular edge-based filleting is usually better since the edge-based filleter handles creating multiple fillets surfaces and also deals (or tries to anyway) with trimming back fillets that collide into one another and putting in corner patches in those areas.

But if you are already working with surfaces, the surface/surface fillet can be handy, and also it is somewhat less complex than the edge-based one, so it can sometimes succeed in building you a fillet surface to work with where the edge-based one can't figure stuff out.

- Michael

Thanks guys