Hi Plasma, filleting is a complex calculation and that makes it a pretty sensitive area.

When you have a lot of junctures between different edges that you are trying to fillet, that tends to make for a fairly complex filleting case because at each of those junctures the fillets from different pieces will try to be intersected and trimmed, and possibly some corner patches put in between them.

So having the fillet go through many juncture points causes it to be a complex case.

For example in your case you're trying to make a fillet that passes through all these different junctures where several edges are coming together:




Also the way fillet works, it makes for a constant radius between things, which means the fillet produced on the angled part will be somewhat smaller in size than the other ones, that's what then makes for the complexity in it then trying to hook up those various pieces. Here I've built some of the individual fillet pieces so you can see what it would have to try to do to connect those up:




So fillet is not so great for your case, it is actually a lot more complex than it looks. I also tried in 2 other CAD programs that also had problems with it as well.


Instead of using Fillet on the end result, I'd recommend filleting your original section curves (select just 1 curve and then when you run fillet you can fillet the corners of the curve) and then lofting between those (w/ Loft Style:Straight), more like this:







That's probably more what you want - the rounded part on the sloped spot is not the same as a fillet, because it's kind of slanted while fillets are more centered on a rail. But this is probably more what you want because the pieces all connect directly without them being different widths like an actual fillet would produce on the sloped section.


Hope this helps,

- Michael