Hi Shazbot, re: "I am trying to do the bottom of that arched shape." maybe it would help if you could show a screenshot pointing to the particular area. Do you mean you're trying to do only some edges around that area that I'm showing above instead of all of them? Sometimes that actually also makes things more difficult for the filleter to handle.

One thing I notice in your geometry is that the bottom of the hood part is not actually a totally flat piece, it's close to being a plane but is instead some kind of sweep or something like that rather than a plane - it generally does help if things that are close to being flat are made from trimmed planes rather than a flat sweep surface or almost-flat in this case.

- Michael

Sorry, I should have been more precise, this image shows what I need to fillet, so you know, what you did works fine on my end too, just not what I am looking for. See if you can fillet this, I certainly can not.

Hi Shazbot, ok yeah I see doing just those ones are not working properly - really you haven't done anything wrong there that's some kind of bug in the fillet handling.

It may be possible to get it to work by having a bit more precise geometry though, that bottom face that looks planar is not actually made from a plane but rather some kind of sweep and it's got a slight angle to it. It generally helps when things that look like they're pretty much flat are made from precise planes rather than just swept or lofted geometry that is sort of close to being flat.

- Michael

Hi Shazbot - try the attached model and that should now work for those particular fillets that you want.

I tuned up this object by separating off the hood part, and then slicing off the bottom of it with a line drawn in the Front view so that the bottom area was actually a totally flat and simple plane object rather than a sweep or whatever that was close to being a plane but not quite all the way flat.

I then did an "untrim" of the now slightly too large opening on the main body (untrim is where you select a boundary of edges and then push Delete to remove them), and then re-booleaned the hood onto the main body to make the tuned up result.

Filleting in the geometry library that MoI uses tends to be somewhat sensitive to geometry that is almost planar but just a little slightly squished around instead of actually a regular plane.

Ideally you would not have to worry about that, but it usually helps to make things that are nearly flat to actually be exactly flat planes instead of only "sort of" flat.

For ends of things it can be good to slice them off with a line drawn in a side view so that you know the end is a plane.

- Michael

Ok, good to know! I guess the best way, I can think of, to do it differently would be to fillet every edge like you did, delete the unwanted faces, then boole union with the other piece, and it worked! Sometimes bugs are good because they allow you to adapt to different situations and come up with a different way of doing things. (: Thanks for the help Michael!

Hi Shazbot, yup sometimes if you can get just some fillet pieces from somewhere else it's possible to splice those into place using trimming or booleans.

That's why if the filleter failed to figure out how to finish everything up but was able to generate some fillet surfaces it will try to spit out those surfaces so you might have a chance at still using them.

Your model is coming along nicely!

- Michael