Hi Gunter, it kind of looks like there is a little shelf-like structure in this area here:


I'll see if I can clear that out for you to give fillets a better chance.

- Michael

Hi Gunter, please try with this attached version:





- Michael

Hey Michael, you're right, I deleted that rectangle and it worked!
Thank you so much!
Gunter

Hello,

Booleans can be a good option in this case.

1. Draw solid > Box
2. Draw curve > Circles aligned to Box
3. Select circles, Construct > Boolean > Isect
4. Select box, Construct > Boolean > Diff, select isect solid
5. Draw curve > Circles, align, select circle, Construct > Extrude
6. Select hollowed box solid, Construct > Boolean > Diff, select cylinder
7. Fillet box / cylinder edges
8. Fillet inside box edges

Hey OSTexo,

This is very helpful, thank you!