Boolean multiple extruded curves


#1

Hello all,

Trying to cut out some curves from a Breb which I extruded with WeaverBird’s thicken.
When I use one curve all works fine, but when I select multiple curves things go wrong and I don’t get a proper CutOut.

Do I use the wrong approach here?

Many Thanks, Robert

BooleanTest_01.gh (11.8 KB)BooleanTest_01.3dm (134.9 KB)


#2

So after a little bit more of experimentation, i have found that by baking out the “MeshDifference” node, two meshes get created, one for each curve that’s in the scene. So that explains why I have no open holes in the model. I discovered that by doing an extrude for each curve and feeding those in the “MeshDifference” node; I get the desired result.

Could anyone please elaborate why the first approach would not work and if the example in this post is the right one or is there a more sophisticated one?

Many thanks,

Regards, Robert


#3

Did not have time to continue this little project, but now I would like to pick it up again.
As I wrote; the problem occurs when I have more then one curve to do a cut out.
I tried to join the two with the merge node but they still show up as “two closed planer curves”.

This is just a simple setup to test the principle, in the end I will have many mure curves to be cutted from the Mesh.

Many thanks.

Regards, Robert


(Giulio Piacentino) #4

Hi Robert @VisualConduct

you need to flatten these two. In the end, the larger definition you post can be simplified, and this would be what you could have asked to get an answer more quickly: why do the datatree below gets subtracted from different meshes?

The answer is that a tree is a list of lists. Because this component Boolean-subtracts a list of meshes from a list of meshes, a tree (here two lists in B) requires also two input lists in A. Because there is only one list with one item, A gets used twice for each of the lists in B.

BooleanTest_02.gh (348.2 KB)