Joint between hoop and spine

[tedbradley314]

Hi folks, I need a bit of help with a joint. I want to join 30+ hoops to a spine, equally spaced apart. I have each of the components designed already. 

The hoop has a channel in it that's 0.4" tall with a 10" radius - the exact same as the outer dimensions of the spine. I tried a cylindrical joint with the cylindrical faces (outer spine face and inner hoop channel face) and a planar joint with the top planar face (top of spine and bottom of hoop channel). But it's not joining the way you would expect. 

What's the best way to join these? What's the best way to space them equal distance apart? 

See attached for file. 

[g-andresen]

Hi,

1. create joint origins on both

2. Join them with rigid joint using 1.

günther

[tedbradley314]

Hi Guenther, thanks for your response.

- Can you expand on this?

- Which faces/edges should I add the joint origins to?

- If I use joint origins should I manually set the angle of the hoop with respect to the spine? 

- The hoops are inserted from a separate drawing; I tried adding a joint origin in the source file for the hoop but it didn't appear in the assembly file.

- Why is the cylindrical joint not working? 

- Why is the planar joint not working? 

- Why is an edge to edge joint not working? 

[laughingcreek]

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@tedbradley314 wrote:

- The hoops are inserted from a separate drawing; I tried adding a joint origin in the source file for the hoop but it didn't appear in the assembly file.

Make sure you SAVE the source file, and then when back in the assembly file, you have to update it to reflect changes (yellow triangle)

Can you make save a copy of your file with the links to the imported components broken, and attach that.  its a pain dealing with .f3z files on our end.  we can open .f3d files directly without having to save or upload anything.

[tedbradley314]

I realized the plane to plane joint was not working because the plane on the hoop channel inside surface is a plane, whereas the top surface of a rectangular cross section coil is not a plane.

I realized the cylindrical joint was not working because the cylinder on the hoop channel inside surface is a cylinder, whereas the outside surface of the coil is a vertical cylinder but I'm trying to get my hoops to line up orthogonally with respect to the spine.

So instead I created a new channel using the exact subtraction of the coil body from the hoop body. 

However, I still can't get them join properly. 

In any case, the exact join isn't paramount. I really just need proper position since this is for visual concept purpose only. I think the ideal would be to use Create > Pattern > Pattern on Path (with orientation set to "Path Direction") and repeat the hoops along the spine outer edge. However, for some reason when I do this the hoops rotate 90deg up over the distance of the coil. See picture below where hoops start in the center of spine and by the end of the pattern repeat they're on top of the spine. 

I've attached a .f3d of the file. 

[tedbradley314]

Hi folks, just wanted to check in and see if anyone knows why the

Create > Pattern > Pattern on Path (with orientation set to "Path Direction")

has the pattern/object rotating 90 degrees over the distance of the path? 

Thanks

[wmhazzard · Accepted solution]

I don't know why the hoops rotate around the path but a way to get around it is to center the hoops on the path, that way the rotation will not show unless you have a feature in the ring. 

[laughingcreek]

The pattern on path tool and the sweep tool both suffer from this limitation.  things always twist around lines that twist through 3d space.  They added guide rails and guide surfaces to the sweep command to help with this issue a little while back, but have yet to address it for the pattern on path tool.  @wmhazzard approach is probably the best work around your going to get.  

[tedbradley314]

Great, thanks to you both. This solution will work great for what I'm trying to do.