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I have done this steps (image1):
1. Clone a mesh like Houdini CopyOp.
2. Cutoff for this clone.
3. Weld points to obtain single boundary.

At this point I would like 'procedurallize' some actions that I need to do (handly done in image2)
4. Select boundary.
5. Duplicate edge boundary.
6. Apply a Shrink wrap o construct similar procedure to obtain 'extrapolate' edge boundary to shape.

Image1


Image2

I found this article and compund, and as note says, from SI 2012 it have own methods to get boundaries from components. However I don't see any ice attribute like 'EdgeBoundary'.

Then there are some attribute to get boundary edges?

I have found this approach but from get VertexIsBorder I obtain all share edges for points that condition is true. How I could get only 'EdgeIsBorder' from these border points?

Hi,
I like the intention but since you mentionned houdini a simple question : why spending days to find how to do that in soft while in another package this nearly is a 3 clic operation ???

Well, this have a easy answer. I'm not a math brain profile, and procedural thinking is hard for me, so don"t matters the software in this question.
However, eventually I have to model some stuff that it looks propertly using procedural methods, so I try.

I'm a Softimage user from XSI 3, and have been use this package daily, so where I don't be enough by procedural it's very easy for me do it by hand modelling.
In other side I messing arround with Houdini from version 8, but I never it used seriously. Also at current day I keep seeing Houdini as not user friendly for traditional modelling methods.

Despite this and come back to the topic, I tried build the same in Houdini. I have to say that you have reason in your affirmation. However I have should asked in Houdini forum how to build a cutoff for CopyOp, and now I'm locked that the group sop gets only connected points/poly islands.

You can try using EdgeToNodes for this. It outputs an array of nodes (samples) per edge.
If the array size is 2 it should be a border edge(?) No idea if this works.
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edit .. turns out the size of the array is always 4. But if the edge is on the border, you'll find -1 entries in the array. That's how you could identify them

Thank you for your reply rray. Finally I used the compound isBoundary above linked. However I will try your method.

Now I'm locked into step 4 and 5.
By one side IsBoundary return an array with index edges
In the other side I have a get self.PointPosition to ClosestLocation of target geometry acting as deformer like ShrinkWarp.

I would like filter this self.PointPosition with Points of the edges from isBoundary. I do not found how to get this data.

Essentialy I would need get each point of the each edge of which I know its index (data from IsBoundary).

I have seen VertexIsBorder attribute that is useful for me.
So I don't need find the way to get points from edge index returned by isBoundary compound.

Finally I have completed this personal excercise, and I wish to share here a videotutorial that I have been done. Thanks so much the people for its help.

Copies with cutoff in Softimage

Too I wanted try to do the same excercise in Houdini, and I have been a great experience.

CopySOP with cutoff in Houdini

PS. My apologizes for my bad english.

Very nice. Do you think it is possible to have a progressive or stepped reducing in size to fill more area?