topic Re: Cannot mitre near-tangent sheet ends in Fusion Design, Validate & Document Forum

Cannot mitre near-tangent sheet ends

kmanuele — Tue, 25 Jun 2024 01:36:12 GMT

I swept a triangle along a path, and the resulting 'solid' has sectioned faces. I need to fillet an edge but get the title failure - presumably because of those sections? How can I fix this?

Thanks in advance.

Re: Cannot mitre near-tangent sheet ends

TrippyLighting — Tue, 25 Jun 2024 14:57:46 GMT

The trick here is to use a Sweep with twist. That will simplify your design a lot!

Make sure to fully constrain an dimension you sketches 😉

Re: Cannot mitre near-tangent sheet ends

kmanuele — Wed, 26 Jun 2024 17:26:12 GMT

Thanks, though it does have a twist -- 90 degrees. Here's a simpler model, with similar segmented result:

I find that the sweep doesn't always segment the results. Not sure what determines that.

Was able to solve by filleting the profile before sweeping.

Re: Cannot mitre near-tangent sheet ends

TrippyLighting — Wed, 26 Jun 2024 19:12:47 GMT

@kmanuele wrote:

Thanks, though it does have a twist -- 90 degrees.

Right, that matches the hand drawn curve to made in your design.

@kmanuele wrote:

I find that the sweep doesn't always segment the results. Not sure what determines that.

I would love to know this as well 😉

@kmanuele wrote:

Was able to solve by filleting the profile before sweeping.

That isn't a solution, it's a hack so you can continue with your hand drawn curve. That curve has severe tangency issues and that is the reason you cannot fillet the solid.

Re: Cannot mitre near-tangent sheet ends

laughingcreek — Fri, 28 Jun 2024 18:39:21 GMT

the hand drawn paths in both models have "kinks" in them the perfectly coincide with the breaks in the swept surfaces.

the swept results are what I would expect from this input. I would suggest going back and looking at how @TrippyLighting set up the sweep in the file he posted in massage 2. It wasn't done the way you did it in your second example (which is why his works).

Re: Cannot mitre near-tangent sheet ends

kmanuele — Sat, 29 Jun 2024 16:57:06 GMT

Actually, the curve was not hand drawn. It was a spiral derived from a coil, unedited. Was under the impression this was the recommended method. I've attached my process. Why would this not work?

Re: Cannot mitre near-tangent sheet ends

jhackney1972 — Sat, 29 Jun 2024 17:14:24 GMT

Responding to your first post. You can create a fillet shape, along the edge you specify, by Sweeping a profile along the edge. Please note, I changed your original Sweep to a Sweep with Guide Surface as well using it on mine. Model is attached.

Re: Cannot mitre near-tangent sheet ends

kmanuele — Sat, 29 Jun 2024 17:22:55 GMT

Follow up observation, it looks like the path in TrippyLightning's method is straight, and the sweep twisted?

I want the path to spiral also.

Re: Cannot mitre near-tangent sheet ends

laughingcreek — Sat, 29 Jun 2024 18:03:46 GMT

@kmanuele wrote:

Follow up observation, it looks like the path in TrippyLightning's method is straight, and the sweep twisted?

I want the path to spiral also.

a straight path with a twist is how you create a spiral-

Re: Cannot mitre near-tangent sheet ends

kmanuele — Sat, 29 Jun 2024 18:06:31 GMT

Thanks for the file and effort. A few questions, if you could indulge me?

How did you generate the spiral curves (sketch 20 and 25)?

In the two sweeps, the "guide surface" seems to be the XY plane. How does this generate the twist?

Thanks for the tip on sweeping a second profile along the edge for the fillet. It works in my model.

Re: Cannot mitre near-tangent sheet ends

TrippyLighting — Sat, 29 Jun 2024 18:14:59 GMT

@kmanuele wrote:

Actually, the curve was not hand drawn. It was a spiral derived from a coil, unedited. Was under the impression this was the recommended method. I've attached my process. Why would this not work?

Who recommended that ?

Edges that are projected into sketches very often have curvature problems, which is exactly what @laughingcreek is showing and which is why I prefer to work with edges of surfaces or solids, instead of projections into sketches.

I have reported that undesirable projection behavior for several years now, and believe that it recently has gotten some attention.

Re: Cannot mitre near-tangent sheet ends

TrippyLighting — Sat, 29 Jun 2024 18:20:03 GMT

@kmanuele wrote:

Follow up observation, it looks like the path in TrippyLightning's method is straight, and the sweep twisted?

I want the path to spiral also.

Explain why you want the path to twist also.

If you edit the features in the timeline of my model you should be able to see exactly how that was created.

Re: Cannot mitre near-tangent sheet ends

kmanuele — Sat, 29 Jun 2024 18:31:47 GMT

Apologize if I am mixing up responders, and thanks to everyone. Autodesk recommended the method to create a spiral in a tutorial:

"How to create a 3D sketch spiral or helix in Fusion"

can't attach the URL

Re: Cannot mitre near-tangent sheet ends

kmanuele — Sat, 29 Jun 2024 19:10:57 GMT

I was assuming the "projection from a coil" method, which generates a spiral path, was the method to use.

Curious that I can use your method to create the same shape, without the surface segmentation appearing, and can thus fillet without problem.

So thanks, and thanks to all.

Re: Cannot mitre near-tangent sheet ends

TrippyLighting — Sat, 29 Jun 2024 19:45:55 GMT

@kmanuele wrote:

I was assuming the "projection from a coil" method, which generates a spiral path, was the method to use.

Curious that I can use your method to create the same shape, without the surface segmentation appearing, and can thus fillet without problem.

So thanks, and thanks to all.

Actually, we have to thank you!

I've looked into this a bit deeper, and it is clear that the "sweep with guide surface" creates the problem even when I use a "perfect" edge as the path. I will report this as a bug!