Hi Pilou, seems to have normal fillet results over here.

Here is the model using the boolean merge method:


Here is what I get with a fillet of radius 2:



It looks like in your case you may have filleted the original curves instead of the solid?

- Michael

< It looks like in your case you may have filleted the original curves instead of the solid?
no :) (same 3dm file than above) construction lines are erased!
Maybe it's the corner angle who makes problem? straight line / curve? Continuilty maybe impossible?
Not so bad but curious :)

Hi Pilou - that is actually working normally.

By selecting just the top loop you are telling MoI that you do not want to fillet the side pieces and that those should remain sharp.

To keep those edges sharp means that the fillets will have to be constructed in the way that you show - the only way to make them rounded in that area would be to also round that side edge as well.

The only other alternative would be to open up a gap in the model, like this:



The area shaded in red there would be a hole in the model.

It isn't possible to be simultaneously sharp and rounded and connected together all at the same time...

- Michael

Ok Perfect explanation ! And not obvious at first view :)

Despite of that result is not so bad, no hole, complete volume :)

Hi Michael

Thank you very much for your reply.
The answer is simple - the rail cannot be with angles.
This pretty much solves the problem
Thanks very much for additional tips.

HI Pilou
Thank you for the tutorial. This is really easy solution.

Regards
Olga