topic Re: Fillet is distorting a face in Fusion Design, Validate & Document Forum

Fillet is distorting a face

vid.kok — Mon, 24 Aug 2020 21:30:02 GMT

Please someone explain to me how to replicate what I created in SolidWorks in Fusion 360.

The model in SolidWorks:

The model in Fusion 360:

Fusion 360 distorts the upper face on the model so it is no longer round while SolidWorks doesn't do that.

I attached the f3d file.

Re: Fillet is distorting a face

TheCADWhisperer — Mon, 24 Aug 2020 21:44:50 GMT

Zip and Attach your *.sldprt file here.

Re: Fillet is distorting a face

Phil.E — Tue, 25 Aug 2020 02:19:45 GMT

Thanks for posting. This does seem a little strange, thanks for the example.

There are two ways:

Use a radius less than about 3mm, or greater than 8.06mm

Or use a variable fillet radius similar to this:

It's not clear why it would distort at any range of values, so this is a good example to show the dev team.

Thanks!

Re: Fillet is distorting a face

vid.kok — Tue, 25 Aug 2020 05:50:25 GMT

@TheCADWhisperer I attached the .sldprt file.

@Phil.E Unfortunately neither of the two options is valid for me.

Re: Fillet is distorting a face

algor_neil — Tue, 25 Aug 2020 12:13:59 GMT

Solidworks has options of "keep edge" or "keep surface" for overflow fillets like this, you need keep edge to prevent that face getting distorted. Looks like 360 is using keep surface.

Re: Fillet is distorting a face

TheCADWhisperer — Tue, 25 Aug 2020 13:48:28 GMT

~~How would you manufacture that feature on the SolidWorks part?~~

Never mind.

See Attached file.

Edit: I just realized that I did wayyy too much work (and made a mistake, but I have to get some other work done while you chew on this one...

Re: Fillet is distorting a face

chrisplyler — Tue, 25 Aug 2020 13:21:27 GMT

I don't understand the desired geometry.

If the angled fillet is uniform, and basically you're cutting the cylinder off further down into the fillet on one side than you are on the other, then of course the cut-off surface is no longer going to be a circle.

Also the base of the fillet isn't going to be a circle either, since it's on an angle relative to the cylinder.

https://knowledge.autodesk.com/community/screencast/14dd861e-6d79-4534-9f4b-f90a104cef45

Re: Fillet is distorting a face

Phil.E — Fri, 28 Aug 2020 00:20:36 GMT

Thanks for letting me know.

I'm just curious about your design. What fillet value is expected to be used, and is that at a uniform radius? Does this part "fit" inside another part, where precise fillet radius and tolerances are key? Just asking because the differences are in the mm range, so probably not even visible to the naked eye. I don't mean to make excuses for Fusion, rather I'm trying to understand how the fillet is critical. This will help prioritize the issue at hand.

Re: Fillet is distorting a face

vid.kok — Thu, 27 Aug 2020 15:47:14 GMT

The part that I attached in the original post was just for a demonstration.

Here is the actual part that I am working with:

The fillet that Fusion 360 creates is just not aesthetically pleasing and I am sad to hear that there is no walkaround except for the @TheCADWhisperer's solution which s very complicated and time consuming.

I guess I will have to export the part from Fusion, apply the fillet in SolidWorks and import the part back to fusion. And this sucks because I lose the design history of the part.

Part with R3 fillet applied in Fusion:

Part with R3 fillet applied in SolidWorks with "Keep edge" feature enabled:

Re: Fillet is distorting a face

Phil.E — Thu, 27 Aug 2020 15:51:33 GMT

Got it. That's a better example. Thanks!

The closest I could get without too much trouble is using a variable radius fillet, this may not be the best solution for many reasons. Just posting to show what is possible today.

Re: Fillet is distorting a face

vid.kok — Thu, 27 Aug 2020 16:16:48 GMT

The problem with a variable radius fillet is that the part is then not machinable on the whole range with a R3 ball end mill.

Can you pass forward a suggestion to implement a "Keep edge" feature?

Re: Fillet is distorting a face

MRWakefield — Thu, 27 Aug 2020 22:37:13 GMT

I could be wrong but I'm pretty sure you're not going to be able to machine all of that fillet with an R3 ball end mill 😉 Have you run a machining simulation on it or modelled up a 6mm ball end mill and tried offering it up to the model?

Edit:

To confirm my suspicions I opened your model in SW2020 and added a 3mm fillet using the 'Keep edge' option. I then performed a curvature analysis. here's a screenshot:

You'll see a radius of curvature of 2.2mm is being reported where my cursor was placed.

Edit #2:

I also performed a check on one of the fillet faces:

As you can see, the min radius on this face is 1.885mm which you won't be able to machine with a 6mm ball end mill.

Re: Fillet is distorting a face

chrisplyler — Thu, 27 Aug 2020 22:37:14 GMT

@vid.kok wrote:
The problem with a variable radius fillet is that the part is then not machinable on the whole range with a R3 ball end mill.

Yeah...uh...I'm pretty sure the SW part isn't either.