I need to have filet on top of this letter but fusion will not let me.

[djon_3V3]

Hi there.

I spent trying ways to have this letter have a 1mm filet on top, but could not figure really why it gets rejected.

Can somebody please help me analyse the root cause? (file attached)

Thanks. 

[jhackney1972]

You can add up to a 0.4 mm fillet to the top edge, over that the profile's corners are too tight! Model is attached.

[djon_3V3]

Hi @jhackney1972 

Thanks for your response, it indeed works.

However, i wonder how you did. I must be doing something wrong or not doing something great, i can not get the same result as yours. 

Can you please share a screencast on your method, i still can not get there.

fusion says "Nah"

Thanks a lot, have a great day.

[g-andresen]

Hi,

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@djon_3V3  schrieb:

Hi @jhackney1972 

Can you please share a screencast on your method, i still can not get there.

---

take a look at the screencast

günther

[jhackney1972]

I am not ignoring your message but @g-andresen covered your needs quite nicely in his Screencast.

[djon_3V3]

Thanks to both of you for your input.

The problem i face is not really how to fillet, but why did that hang? I am trying to understand the fillet in order to be able to predict its behavior and not play catch-up.(modify, fillet,  see if it enables me to go to the desired fillet or not, 20 goto 10) I have a whole logo to reproduce, and spending that time on a single letter is not a good sign.

I re-did that letter with splines, from scratch and it will or will not accept to fillet based on chaotic rules. I would love to extract some knowledge from that.

At the moment, i've determined that:

- fusion can fillet a spike, so fine parts do not cause problem

- fusion can not have crossing fillets on thin bridges, which must at least twice the fillet thick.

- fusion seems to have problems with the closing points of a closed spline. Not sure what or why but fiddling with them sometimes gave better outcomes.

However, sometimes it fails for reasons that are not within the three above.

Any idea or knowledge will be highly appreciated.

[djon_3V3]

As an example, please see the object linked. For some reason totally not related to the three rules above, it will not take a fillet over 0.029mm.

However, if i scale the sketch by 10, extrude by 30mm, i can now fillet by 1.1mm. Fillet limit does not scale linearly with object size. I would have expected it to be limited to 0.2mm, then.

But...

If i scale by 100, i can not go over 11mm.. Go figure. Still, it does comply with all three discovered rules and fails for an unknown one.

ridiculously limited fillet

[djon_3V3]

Maybe this belongs to the Bug section of the forum.

That result does not look valid to me.

[djon_3V3 · Accepted solution]

Definitely looks like a bug.

I opened a bug post  and for sure, a smart mind from Autodesk had a brilliant test to show that there was something fishy.

https://forums.autodesk.com/t5/fusion-360-support/fillet-won-t-go-near-any-acceptable-radius/m-p/105...

I'll close this post and mark this as the solution so that people can jump to the correct place if they encounter this too.