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Splitting a hollow cone by a helix
BrainStone
Member Posts: 5 ✭
Hi there. I would like to create a hollow cone with a swirl.
So my idea was to split it into a few parts using a helix. It took a while to figure out how to turn the helix into a surface but now since that is done, the splitting is what's causing a headache.
Here is the cone and the helix surfaces
Now here is what happens when I try to split it. I haven't found a way to select all 3 surfaces at once for the splitting.
And if I disable "Keep both sides" I get this. Which seems to be better but still won't split at all.
I assume I'm just missing a minor detail, so any help is appreciated!
Comments
The split dialog box suggests that the Split tool only allows for splitting an entity into two pieces in that it asks for a singular entity to split with and asks whether or not to keep both pieces. Perhaps thickening the surfaces to .001" and using the Boolean (subtract) tool to create the three parts would satisfy your desired results. - Scotty
Thank you. That worked!
Had to use 0.01mm in both directions, else it refused to work, but that's fine
None of the 3 helical surfaces pass completely through the cone so that it can be split. I'd suggest creating a solid sweep of 1/3 of the helical area and using boolean intersect to get 1/3 of the volume. from there you can pattern it or edit it as you need.
Or depending on design intent maybe a similar method using splitting faces might be needed.
add in an offset cone surface to use for a split of the boolean intersect.
On that thought would it be possible to join the 3 helix surfaces into 1? That should cleanly split the part I believe.
I got 2 of the surfaces to boolean but it wouldn't join the 3rd for some reason. I could split the cone with the boolean-ed surface. In theory yes that should work fine.
I suppose joining the 3rd surface creates a sorta zero thickness sorta situation, so it can't do it. would have to be done in 2 splits then.
I don't think it's a zero thickness situation, more like a front side vs back side situation. If you have two surfaces sharing an edge they both can agree on matching the orientation of the faces on both sides of said edge. (Unless you do a mobius strip or something like that) As soon as you add a third surface meeting said edge you've guaranteed that face #3 is going to have opposing normals to one of the other two faces sharing the set. Imagine doing a split then flipping the handles to try to decide which "side" of the split to keep. How do you define a "side" when you have a group of face normals that opposes itself?
@Derek_Van_Allen_BD that's much better explanation… I knew it was something like that that I was trying to get at but couldn't put the words to it. Thank you.