Question about sweep.

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 From:  stevecim
4937.1 
Hi All

been playing around with flow and sweep, I used flow to place a grid of squares around a sphere, worked great, them I used sweep to "thicken" out the curves. worked about 80%, ended with 4 sections that look like this.










I tried sweeping 1 section at a time, still ended the same.

Am i doing something wrong with sweep?

Cheers, Steve

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 From:  Michael Gibson
4937.2 In reply to 4937.1 
Hi Steve - generally to get mitered corners on a sweep you need to have a planar curve for the path. Curves that are arcing around in 3D don't necessarily have the same kind of clean juncture between them where the pieces meet unless they come to a planar area in the region where they touch.

For something like that you may need to put in a profile section that's at a 45 degree angle in the original shape, and flow that and use that angled profile as part of the sweep rather than relying on sweep to miter the ends which instead involves intersecting and trimming the sections against each other which then will not work if they don't meet up in a planar juncture.

- Michael
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 From:  Michael Gibson
4937.3 In reply to 4937.1 
Hi Steve, or actually since in this case some areas were able to get mitered even though they're on 3D curves, take one of the pieces that was successfully constructed, like this one here:



and then delete all the other ones to its left and right and then you can probably replicate that good one around with Transform > Array > Circular.

- Michael
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 From:  Michael Gibson
4937.4 In reply to 4937.1 
Hi Steve - also if you zoom in a ways on the seam areas of where the 2 tubes cross each other you can see why it's difficult for these kinds of things to get auto mitered:





You can see that there's a rotational difference between the 2 shapes there, the rotation would be a lot more obvious on something that wasn't a circular shape.

In some areas that rotational difference was small enough that it was ok, but in the ones that failed it happened to be a bit larger and if it's too large it significantly complicates the miter trimming mechanism. The mitering can only work if the surface pieces meet up in a more precise way, so usually it only works if the paths are 2D curves.

In the future I do want to add in a different corner mitering style which would to put in a slanted profile and then sweep to that slanted profile rather than doing an extension and trim type method, but sweeping to a slanted profile produces a slightly different kind of shape. You may need to do a manual slanted profile approach to make stuff like this work now though.

- Michael

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 From:  stevecim
4937.5 In reply to 4937.4 
Thanks Michael.
been playing around a bit with sizes, found if I get the right combination of sweep profile and sphere size, it would sweep OK :)
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