Hello,

You can try to first scale the whole model 10 times bigger, by doing that I was able to fillet this specific edge up to 0,7 m.

Hi Steve,

I had a shot at this one and it's a dog! I think the combination of the surfaces you've got there has MoI filleting stumped, there are some situations where the filleting in the library used for MoI falls over, MoI users are aware of this and in some situations they would bring their model into another more mature modeling program to do these sort of bits, one day I do believe that the library MoI uses will be able to do your fillet with ease, it's just that we have to be patient and use other tools in conjunction with MoI which is a normal thing with all software, we can't have one tool that does everything.

I did manage to get some success when changing the units to millimetres, but it would still mean some low level modeling involving separating and trimming surfaces. Sometimes reconstructing the surfaces differently can help, like using sweep instead of loft where the slightly different structure of the surface could be more friendly for the other commands, but that's more on an experimental level to get to know your software better.....I know, most of us just want the job done, unfortunately it's not a perfect world in software land :)

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Hi Steve, it's going to be quite difficult for the edge-based filleter to figure out how to seal up the holes that would be created by a fillet in that location.

Here I'll try to show you what I'm talking about.

Here I have created a fillet surface using the surface/surface filleting mechanism. I did this by breaking your solid model into individual surfaces and then selecting just two of those independent surfaces and running Fillet. This runs fillet in a different mode which is called surface/surface fillet. It can build fillet surfaces in areas where the edge-based one cannot figure things out:



The fillet continued on for a ways, I cut it back to get what I show above.

Now if you look at these areas where the fillet ends, you can see that there would be some kinds of holes created because the fillet pulls away from the main body of your shape:




If that surface was a plane or something simple, it may have a chance to figure out how to fill in that hole. But with all freeform geometry like you have here, the filleting mechanism is not able to figure out what to do about those holes there. That's at least one reason why you would have difficulty filleting that edge.


One thing that can help a lot is if you make that edge to be made up of smooth pieces, rather than having a sharp corner in it. The fillets for a smooth piece will all connect together smoothly as well rather than opening up gaps that need to be filled in which happens with sharp-cornered things like you have there.

- Michael

Hi Steve

I made the block at the front a simpler solid, I would cut out the air scoop after with a boolean difference. Also if you a mirroring make sure the 2 control points near the border are horizontal or you will have a crease when you mirror (see attached picture. 2 highlight point should be aligned). This is the same with your other profiles. also make sure your profiles are aligned at the center Z axis. Its worth checking before you build you shapes because if they are out you will run into all sorts of problems later on.

Hope it helps a bit. Looks like you will also have a tough area with the wing transition, good luck. Look forward to seeing the progress.

Regards

Jamie

Hi Steve, also another thing that could possibly help you is if you select the 2 surfaces that share that edge, and use Edit > Separate to break them apart from the main solid, but they will still be joined to each other.

With that situation the filleter no longer has the complexity of collisions with the surrounding side surfaces to try and deal with for filling in holes, and you can create a fillet successfully similar to surface/surface fillet that way.

It will be a kind of long extended piece like this:



But it may give you enough raw material to work with and cut down.

- Michael

That last option seems to be a goer. It is difficult to create a nurbs version of what was very simple in sub-D. Ive tried this in Solidworks and found it virtually impossible. Good job Sidney Camm wasn't using CAD!

Very interesting, I did'nt know fillet could be used in this way with surfaces.

Marc

Steve,

That's true. Some shapes just naturally lend themselves better to different technologies. There's no "right" or "wrong" here. Sub-ds, nurbs and solid modeling can all do terrific stuff, if you play to their strengths but can be equally frustrating when you get down and dirty with their weaker sides.