I am looking for a way to subtract polycurves from eachother, like a boolean operation, which turned out trickier than I thought (for a noob like me).
The curves are all flat on the XZ plane, so the edges are all intersecting.
I basically want to subtract the curves from each other to create a shape which I then can extrude and still have the original profile curve.
Any help is appreciated.

Boolean SOP, set both to Surface

you can use end SOP to close straight one curve and extrude it along curve normal and than fill the cap, finally use it to boolean with other curves by intersect analysis / stitch SOP or try my Boolean Curve [vimeo.com] HDA to boolean other curves.

Furthermore, if you only want to get the profile curve, perhaps my Get Outline [vimeo.com] HDA can achieve it.

I must say Houdini is so good at solving curve (but does not have a handy curve SOP)…

tamte
Boolean SOP, set both to Surface

Well, it works for subtracting but not for union. For union the overlapping edges remain, I do not get 1 curve outlining the 2 input curves.

@zengchen
I tried your boolean curve hda but for me it doesn't do anything. I can't even pick which boolean operation I want to use.
+1 for your signature though.

blackbeard
Well, it works for subtracting but not for union. For union the overlapping edges remain, I do not get 1 curve outlining the 2 input curves.

they do remain, but polygons are unified
so just append Divide SOP and check Remove Shared Edges if you want just outline

blackbeard
I tried your boolean curve hda but for me it doesn't do anything. I can't even pick which boolean operation I want to use.
+1 for your signature though.

if you do not show the hip, i am hard to do further

tamte

blackbeard
Well, it works for subtracting but not for union. For union the overlapping edges remain, I do not get 1 curve outlining the 2 input curves.

they do remain, but polygons are unified
so just append Divide SOP and check Remove Shared Edges if you want just outline

Awh nice, that Divide SOP made my day. Thanks a lot.

…so, your origin geometry is not curve but polygon?

but why you say "The curves are all flat on the XZ plane, so the edges are all intersecting"?

i am so curious why tamte can get the point from your words. ⊙﹏⊙∥

zengchen
…so, your origin geometry is not curve but polygon?

but why you say "The curves are all flat on the XZ plane, so the edges are all intersecting"?

i am so curious why tamte can get the point from your words. ⊙﹏⊙∥

I'm sorry, now that I read it I see that it indeed is a bit confusing. In my case I'm dealing with circles which are set to polygon but since they can also be seen as curves I called them polycurves although they are much more precisely described as circle polygons, I guess.
Tamte probably just deduced from the term polycurve “Ah, he means the outer egde of whatever n-gon”

Can you share an example image of what you would need to do, or create?