Fillet Hell - which is all too common

[jandyman]

Fillets seem to always be the area that cause me tear my hear out. They seem to fail in all sorts of confusing ways, and always hang me up. I've been thinking that maybe I should be using lofts or sweeps because they are so troublesome. So here is a simple example of what happens to me, in the hope that someone can help me understand how fillets work thoroughly enough to be able to tame them. I've included a video showing what happens, and also the simplified model is attached.

[jandyman]

Fillets seem to always be the area that cause me tear my hear out. They seem to fail in all sorts of confusing ways, and always hang me up. I've been thinking that maybe I should be using lofts or sweeps because they are so troublesome. So here is a simple example of what happens to me, in the hope that someone can help me understand how fillets work thoroughly enough to be able to tame them. I've included a video showing what happens, and also the simplified model is attached.

[jeff_strater]

I think this is a bug, but it might take me a while to verify this.  I'll try to look into it next week.

[jeff_strater]

I think this is a bug, but it might take me a while to verify this.  I'll try to look into it next week.

[jandyman]

@jeff_strater Thanks. I just posted another issue which is possibly related, since this other issue is limited to profiles which are spline curves. It might help narrow down what is happening:

https://forums.autodesk.com/t5/fusion-design-validate-document/quot-body-would-intersect-itself-quot...

[jandyman]

@jeff_strater Thanks. I just posted another issue which is possibly related, since this other issue is limited to profiles which are spline curves. It might help narrow down what is happening:

https://forums.autodesk.com/t5/fusion-design-validate-document/quot-body-would-intersect-itself-quot...

[TrippyLighting]

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@jandyman wrote:

@jeff_strater Thanks. I just posted another issue which is possibly related, since this other issue is limited to profiles which are spline curves. It might help narrow down what is happening:

https://forums.autodesk.com/t5/fusion-design-validate-document/quot-body-would-intersect-itself-quot...

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It isn't. I responded 😉

[TrippyLighting]

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@jandyman wrote:

@jeff_strater Thanks. I just posted another issue which is possibly related, since this other issue is limited to profiles which are spline curves. It might help narrow down what is happening:

https://forums.autodesk.com/t5/fusion-design-validate-document/quot-body-would-intersect-itself-quot...

---

It isn't. I responded 😉

[jeff_strater]

Thanks, @jandyman - it is always good to share issues that you think might be related, because you never know what might be connected.  In this particular case, I think the fillet issue is limited to variable radius fillet.  Adding another point to the VR fillet with any radius other than .2 (even .21) causes failure, even if you limit the range (add two points with a .2 radius nearby, to limit the effect of the .21 or larger point) causes failure.  That smells like a variable radius fillet bug, while the other issue is a sweep self-intersection issue.  I appreciate the added info!

[jeff_strater]

Thanks, @jandyman - it is always good to share issues that you think might be related, because you never know what might be connected.  In this particular case, I think the fillet issue is limited to variable radius fillet.  Adding another point to the VR fillet with any radius other than .2 (even .21) causes failure, even if you limit the range (add two points with a .2 radius nearby, to limit the effect of the .21 or larger point) causes failure.  That smells like a variable radius fillet bug, while the other issue is a sweep self-intersection issue.  I appreciate the added info!

[jandyman]

@jeff_strater 
OK. But I should say that after discovering this other issue with sweeps and lofts when using spline paths, I went back to my model and replaced some of the splines with linked lines and arcs and variables radius fillets became *much* better behaved. Not perfect, but there may be something to using splines that exacerbates the situation with variable radius fillets (and I see some of this with constant radius fillets as well).

It's too bad because splines are so useful and time saving otherwise.

[jandyman]

@jeff_strater 
OK. But I should say that after discovering this other issue with sweeps and lofts when using spline paths, I went back to my model and replaced some of the splines with linked lines and arcs and variables radius fillets became *much* better behaved. Not perfect, but there may be something to using splines that exacerbates the situation with variable radius fillets (and I see some of this with constant radius fillets as well).

It's too bad because splines are so useful and time saving otherwise.