Help with simple pendant case/cover

[Anonymous]

Okay, guys feel free to beat me up on this one but I could really use some help on this design. I'm about to be freed up from school for the summer which is going to give me additional time to continue my studies with Fusion 360 but in the meantime I'm attempting to design a "cover" for an oval pendant which would essentially cover just the outside of the pendant itself and perhaps 1-2mm of the surface from the outside in. I'd like for the entire front and back of the pendant to be visible, though so this "cover" would almost look like an oval ring that would wrap around the pendant. Hopefully that makes sense. I believe I've gotten the general design down, however I'm not sure how to "carve" out the center of the oval "cover" so that the pendant will snap into place.

In case it helps, here are the dimensions of the pendant:

L = 30.1625mm

W = 25.4mm

D = 7.9375mm

Any help is greatly appreciated! Thanks in advance!

[laughingcreek]

You might want to post your attempt, we'd have a better idea what your after.

Here's my thought-

[Anonymous]

I've attached what I have come up with so far. I like your design, however the pendant actually doesn't have the loop for a chain anymore so it's literally just an oval. I guess I was just unsure whether shell feature was the correct one for hollowing out the inside of the oval or if there's a different method/tool suggested. For my design I used the shell feature to reduce the thickness of the inside and then the fillet method/tool to round the edges. What's your thoughts?

[laughingcreek]

I'm away from a computer for a few days, so I can't open tomorrow file, but I'm sure someone will stop by and comment.

For me example, you can get it to go all the way around by editing the sweep.  Delete the filet also.

[chrisplyler]

That looks fine to me. You COULD just sweep an overlapping ring profile around the perimeter of the pendant, and then combine/cut/keep the pendant shape out of the ring shape, such that the ring then fits perfectly.

[Anonymous]

That's a fantastic idea; not sure why that didn't come to mind.

So...create the pendant model in 360 and simply apply sweep. Silly idea perhaps but what's the best way to go about creating oval and/or tear drop models? I have my steps jotted down for how I achieved the model you see in my screenshot but boy did it take me some time to do! Lol. I'm sure I did a lot of unnecessary steps to achieve the result. I couldn't appear to get both x and y axes to show (only y) on the model sketch in order to set the correct dimensions for the pendant.

Loving 360 so far but obviously a lot to learn still.

[chrisplyler]

Technically speaking, Sweeping such a profile (for the ring) around an ellipse shape is not going to get a perfect fit onto the pendant. I mean, at the long ends of the pendant, the top and bottom slope is lower than it is on the short sides. But the Sweep around it isn't going to change as it goes around. That's why I suggest having the profile overlap into the pendant material, doing the sweep, and then cutting the overlapping bit back out using the pendant as a tool. It makes a mating surface between them, but still the exterior edge of the ring will be consistent, while the pendant is not consistent.

In the video below, I'll show you how I like to do such shapes. And you COULD also do the ring in the same manner if you add four profiles for it outside of the four used for the pendant. Make one component, Loft the pendant, make a second Component, Loft the ring around it in exactly the same manner. This method should make the geometry match exactly, although whether the extra work is worth it is up to you.

[chrisplyler]

Now, I like that method, but it's more work than what I'm about to show you, and it's not going to lend itself to a teardrop shape as easily. So I'm going to show you a method that uses the Patch workspace.

In the Patch workspace, you basically construct the desired surfaces only (there will be no solid geometry yet), and when you're all done you Stitch those surfaces together (connecting their edges such that it becomes one water-tight unit) and it turns into solid geometry. It's easier than solid modeling some shapes, and it will work just as well for a teardrop as for anything else.

[Anonymous]

Chris I really appreciate the intuitive instructions and videos! I'm definitely going to try both methods to test the results and how I might use these methods with different projects.

The last question I have is on sweeping. I'm still not 100% on how to achieve the result you're describing . In your original e-mail you described the sweeping process with a screenshot. I studied the sweeping process a bit more last night but still not quite sure about how to sweep an overlapping profile around the pendant. I'm sure it's easier than what I'm trying to do. If you're able to give some guidance there I'd be thankful but if not that's okay, too. You've already given me a ton to work with and I really appreciate you giving your time to help me! 🙂

[chrisplyler · Accepted solution]

Okay. I made a new video, start to finish.

I made the pendant with the Patch>Loft tool, and made the ring with the Model>Sweep tool.

Notice: I did the setup for the pendant differently this time, using a "controlling" sketch and two Offset Planes, instead of four Offset Planes. In this way I can control the pendant more easily, by just editing sketch dimensions instead of having to go back and edit each Offset Plane distance.

Notice: The profile I drew for the sweep overlaps the material of the pendant. This is only desired in this case so that you will have some meat to cut back out of the pendant to achieve a good fit. See how the long sides fit differently than the short sides, as I tried to describe earlier? That's because a Sweep keeps exactly the same profile no matter the path. It does NOT distort it to match the changing slope of the pendant. If the pendant was a circle, it wouldn't matter, but since it is an ellipse, the slope changes. But the angle I built into the ring's sweep profile does not. That's the whole reason that we want to overlap the profile with too much material and cut that material out afterwards. If you want the ring to distort and fit properly and consistently around the pendent, you're going to have to Loft it around with four profiles, or build it in the Patch workspace. Now that I think about it, you could just Patch up a second pendant shape slightly larger than the first, combine cut the first out of the second to make it hollow, then extrude a smaller ellipse profile down through the top to make it mostly hole and leave only the perimeter (this method not shown in the video, because I just thought of it).

[Anonymous]

Thank you very much Chris; you're awesome! Your video walk-through really helped me to better understand your earlier post and I plan on attempting this method myself a bit later today. This will help me with other projects that I'm planning to work on as well. Loving the forum and all of the help I've received thus far. Keep it up!