Hi OSTexo, is there a particular fillet radius value you are trying to target?
I loaded your file and for the most part I seemed to be able to get fillets on it, for example here is one with radius 0.2:
But one of the big problems here is that your surfaces are significantly more complex than optimal, with a lot of poles and irregularities in them.
For example your surface here that looks like a simple extrusion:
Is actually a complex surface that collapses together with poles in these areas:
That kind of squished together structure at those pole areas is bad, it is likely that the surface actually goes back and forth over itself in that little area, that is a bad thing for fillets.
Similarly this surface that looks like it may be a part of a sphere or something:
Is actually a kind of asymmetrical warped surface:
That's actually got a pole and actually even worse a kind of "anti-pole" where 2 edges of the underlying surface are tangent where they touch one another rather than being a distinct quad surface patch.
That's a lot of twisting and compression in little zones in each of those surfaces, that is going to very negatively affect additional calculations that try to trace along those surfaces like fillets do.
You'll get a lot better results with cleaner and more simple structured surfaces, you should try to get more things like trimmed extrusions for pieces that are straight in one direction, rather than trying to do it by something like a loft between 2 halves that touch each other at a point.
If your object is a solid, the best way to get a clean structure is to do the initial cut with a curve from the side view, which will automatically produce an extrusion for you as the capped off surface. It will give you a very much cleaner result and will actually be faster to model as well.
Check out this previous post for an explanation and some illustrated steps:
http://moi3d.com/forum/index.php?webtag=MOI&msg=2614.10
Also some of the previous discussion there may be worth checking out, since it pertains to the same kind of technique that you are using here that is giving you bad results later on:
http://moi3d.com/forum/index.php?webtag=MOI&msg=2614.7
Hope that helps,
- Michael
