Hi Glenn,

> The problem with the top part is what I encounter the most when using fillet.
> But if I understand correctly there nothing I can do different to prevent this from happening?
> There is nothing wrong with the way I modeled the solid or something?

It doesn't look like you've really done anything wrong there, I would have thought that should work.

But you may be running into some general problems related to constructing objects at a somewhat larger scale, you may be able to get some more reliable results if your objects are something like maybe 10 units across in size rather than hundreds of units across.

I've attached a reconstructed version of your object, which I did by scaling it down 1/10 from your original size, then extracting the edges and building new lofted surfaces between them. This reconstructed version does not seem to have any problems with filleting anymore.

If this is something that you're running into frequently you might try just generally drawing and creating things at a little bit smaller size, something like having things at around maybe 1 to 50 units across.

Also from the structure of the surfaces, it looks like you're building this by arranging several 3D curves into place and then constructing surfaces between them. I wouldn't really call that "wrong", but it may be slightly better to try and use 2D extruded surfaces when possible, so like in this case here starting with a block and then doing booleans with 2D curves to slice off chunks of the block rather than doing it all with surface construction between 3D curves.


> If it's a bug that can be fixt in the future.
> Maybe it's helpful for you, If I send you a file each time I encounter such a problem?

It does look like it's a bug. Right now I'm not sure exactly what it's sensitive to, unfortunately it's very difficult and time consuming to do a proper diagnosis. Also it's a particularly easy area to introduce new bugs into when trying to change things to fix a particular case. If you run across cases like this in the future it would be helpful for you to send them to me (please e-mail to moi@moi3d.com), if I get several test cases to work with that does help a lot when I would try to do a fix for it.

- Michael