Selecting the entire edge of a face

[tonySWCR2]

I have a plastic component that I require a rubber seal modelling around one continuous edge.

Easy right? Grab the an edge of the component, expand the selection to all tangent edges, promote the selection to a 3D curve, draw a profile perpendicular to it and sweep the profile around the curve. Well, that's how I would have done it in CATIA, but how do I do that in Fusion 360?

I can get a single edge by using the project to 3D and I can slowly work my way round clicking edges, but this is taking too long. How do I select the entire edge and promote it to a 3D curve? (The whole edge is tangent, I'm not asking for miracles)

Any help appreciated.

[TheCADWhisperer]

File>Export and then Attach your *.f3d file here.

[TrippyLighting · Accepted solution]

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@tonySWCR2 wrote:

How do I select the entire edge and promote it to a 3D curve?

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You don't. In the sweep dialogue, you'll see the "chain selection" option, which really refers to "tangent chain selection"  You can then select the profile and path you want to create the sweep with. 

[tonySWCR2]

So Fusion is able to identify a tangent edge chain to use as a guide, but not a selection tool that selects all tangent lines? Anyway, I will have to make do with that. 

Shame it cannot select all of it and create a 3D projection so I can manipulate the spline first.

[TrippyLighting]

Without seeing the model the context is missing for your post to make sense. What spline are you talking about?

[tonySWCR2]

The profile cannot follow the guide curve as it has too tight of a radius. All I want to do it grab the edge, convert it to a 3D spline and then edit the radius. There seems to be very limited tools for 3D splines. 

 

[TrippyLighting]

If you can share that model I can possibly show you a simple technique not involving any 3D curves.

[tonySWCR2]

Thanks

[TrippyLighting]

This turned out not to be as easy as I thought, but it also shows that even if you hade ben able to create that 3D curve (which is possible BTW with the Include 3D option when in a sketch) the sweep would have complained about self-intersecting surfaces.

I rearranged the timeline a little to make parametric changes easier. You should be able to see what I did by going step by step through the timeline.

 

[laughingcreek]

@TrippyLighting - I couldn't get sweep to completely work at that one oblique corner at the back.  obvious why it would have problems looking the curves.  I see it didn't quite work for you either-

 can you think of a way to get sweep to work here? I cant. would have to resort to other modeling techniques to get this part right.

[TrippyLighting]

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@laughingcreek wrote:

...  I see it didn't quite work for you either ...

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If the aim was to create perfect geometry, then NO, that did not work. But we need some feedback from the OP on what the purpose of that design is.

For example, if this was a rubber gasket with adhesive backing cut to length, my question would be: Would you really think that you would be able to apply it reliably around such sharp bends?

You can model a lot of perfect geometry, but if the goal is to create e physical artifact, how are you going to make it?

Before that question is answered I personally would not want to spend time creating the "perfect" geometry.

[tonySWCR2]

@TrippyLighting thank you for looking at this. As you have correctly identified the model is just of an extruded seal that is to be stuck around the lip of the main part. The dimensions in the model I shared are completely arbitrary so it is not essential that the model you generate is perfect but more what the methodology is to get the functionality from Fusion 360 that I want.

Unfortunately, the method you have used in the file you shared is far from ideal. That is not to say you did a bad job, I don't think that, you have been limited by the tools available in Fusion 360. I really don't like having to change one component multiple times so that I can get another components shape, if that makes sense. The model looks very fragile, if I was to change the first component in some way it is likely to cause the second to fall over. In the actual model I am trying to get this to work on the main body is already completed and it is pretty complex so I do not want to have to remodel it.

You speak of being able to 3D in sketch, I looked into this before I posted the original question, my understanding is that you can place lines perpendicular to the sketch plane but for me to draw that working around the edge of the shape would be so inefficient in time it would be quicker to download another CAD package. I am very new to F360 so if there is something I have missed with 3D sketching please share it. 

[tonySWCR2]

I think I have worked out a way to do what I want. I will post it up when I am done.

[TrippyLighting]

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@tonySWCR2 wrote:

... The model looks very fragile, if I was to change the first component in some way it is likely to cause the second to fall over...

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That depends on what you change and even more so when you rely on sketches. 3D geometry is almost always more stable than anything that you can do in a sketch.

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@tonySWCR2 wrote:

... In the actual model I am trying to get this to work on the main body is already completed and it is pretty complex so I do not want to have to remodel it...

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Aha, now we're getting closer to the problem. What that means is that for your current knowledge of the tools techniques in Fusion 360 you have used an unfavorable path. Now you are trying to find remedy in techniques you are used to from another CAD package.

You can project any edge into a sketch including 3D. That is equivalent to converting an edge into a curve. In order to edit some o the projected edges, you'll have to break the link(s) between them and the originating edges.

It is not a workflow I would recommend.