Fillet Problem on Solid

[Anonymous]

I'm very new to 3D CAD and Fusion 360.  I have a solid created from a surface, and I'm having problems with fillets.  It looks like Fusion is having problems with the faces making up the solid in this area.  Any help?

[TrippyLighting]

If you fillet the inside corner this will work.

[Anonymous]

Thanks Peter.  I saw that myself while I was trying to figure this out before posting, but I wouldn't think I should have to fillet that inside corner to make this work.  Doesn't there have to be something wrong with that solid for there to be a problem like that?  Fusion clearly doesn't like that "seam" between the faces to the right of the inside corner.  As I've played around with this model, I've seen other instances where Fusion interprets the boundary between two faces as an edge.  In the example below from the same model, I select the edge shown in blue to fillet, but the fillet extends onto the top of the body.  And in that case, filleting the inside corner doesn't solve the problem.  It just seems like Fusion doesn't treat the body as a single solid, but as a bunch of individual bodies joined together, which seems to confuse it.  Is there something I'm doing wrong?

[TrippyLighting]

You are correct, you should not have to do this!

I've had number of occasions where Fusion 360 filleting did not work and I had to take it into another CAD application to get it filleted.

I believe ultimately this is a problem with how filleting is implemented in the geometric model ing kernel (ASM, an early fork of the ACIS kernel). I don't see this behavior improving, to be honest.

[TheCADWhisperer]

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@TrippyLighting wrote:

... (ASM, an early fork of the ACIS kernel). ...

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I don't understand this statement - can you elaborate?

If you Export the file in STEP format and then open that - does the unexpected fillet behavior persist?

If you remodel the part from scratch in Autodesk Inventor following the same modeling steps - does the unexpected behavior persist?

[TrippyLighting]

Here are 2 wikipedia entries on geometric modeling kernels in general and the Autodesk Shape Manager (ASM). Here is another entry on the ACIS kernel.

[TheCADWhisperer]

I am familiar with ACIS and Autodesk Shape Manager.

I don't understand this wording, "(ASM, an early fork of the ACIS kernel)."

Edit: OK, I see where you got the reference to "forked".

[TrippyLighting]

I guess a more accurate sentence would be a fork of the early ACIS kernel.

[TheCADWhisperer]

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@TheCADWhisperer wrote: 

1. If you Export the file in STEP format and then open that - does the unexpected fillet behavior persist?

2. If you remodel the part from scratch in Autodesk Inventor following the same modeling steps - does the unexpected behavior persist?

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1. If I export as STEP and then Import - I do not see the anomaly.

2. If I remodel from scratch in Autodesk Inventor - I do see the anomaly.

Apparently "forking" the ACIS kernel did not work out so well for ASM.

[Anonymous]

Thanks for answering Peter.  I don't have Autodesk Inventor.  

In this particular case, I can get around it by playing with the fillets.  I would hate to have to go to the step of exporting it and then doing the fillets, because this is a part I'd like to set up to be easily modified with a parameter list.

[TheCADWhisperer]

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@Anonymous wrote:

.... this is a part I'd like to set up to be easily modified with a parameter list.

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I would model from the very beginning very differently, but for whatever it is worth, maybe a simple change in order of operations (see attached).

[TheCADWhisperer]

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@Anonymous wrote:

.... this is a part I'd like to set up to be easily modified with a parameter list.

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I would model from the very beginning very differently, but for whatever it is worth, maybe a simple change in order of operations (see attached).

[Anonymous]

That's interesting.  Thanks for the models.  For what it's worth, I've tried several different ways of modeling it, and I've yet to find anything that works much better than this.  That could well be my lack of experience.  I'd be very interested to hear how you would model it.  One thing I'll note is that the angled "paddle" seriously complicated the modeling for me.  That's one of the reason I used the patch workspace on this particular model.  I have an earlier version with a straight paddle that was considerably simpler.

Thanks!

[TheCADWhisperer]

What is your manufacturing tolerance on the part?

[lichtzeichenanlage]

I'm a beginner, I like to learn so I played around with your file. If I suppress the surface trim I can fillet everything but not on tiny part. There I had to reduce the diameter to 0.9mm

[Anonymous]

For what I'd like to do with it, this would likely be 3D printed, and the manufacturing tolerance wouldn't be too critical.  I would guess that 0.2 mm would be acceptable.

[chrisplyler]

I don't know why yours won't fillet. Mine fillets just fine. But I built mine entirely in the Model workspace, so...

[Anonymous]

Can you attach the file?  I'd like to see how you did it in the model workspace.  I couldn't figure out how to angle the "paddle" part in the model workspace.  Thanks!

[chrisplyler · Accepted solution]

Here you go...

Sketch 2 is the slanted shape of the paddle, and Sketch 3 is the curve of it.

[Anonymous]

Thanks Chris.  I'd still like to understand why the solid as I created it doesn't work, but I really appreciate seeing an alternate workflow, and it seems like keeping it all within the model workspace solves a lot of the problems.