Interpolate curve through points in data tree


Not very inviting… I didn’t bother looking at the original file.

Here is a variation on your version ‘02’: (10.2 KB)

P.S. Here’s another idea, a little goofball… Slider in blue group sets ± rotation increment. (9.8 KB)


Hi Guys,

Thanks for the responses.

I could get the relative item to work with the ‘line’ command, but it still doesn’t interpolate the curve because it isn’t restructuring/remapping the points.

(I know there are other ways of achieving the form and getting the points, but my points come from panels on a surface lofted from two circles, so I have to work with the structure I have currently. And yes, there are a lot of irrelevant GIS components I had been playing around with in this file)

What I am really trying to do is get items from a tree in this pattern:
{a}(0),{b}(1),{c}(2),{d}(3),{e}(4),{f}(5),{g}(6),{h}(7),{I}(8) - interpolated curve through points
{b}(0),{c}(1),{d}(2),{e}(3),{f}(4),{g}(5),{h}(6),{i}(7),{k}(8)) - interpolated curve through points
{c}(0),{d}(1),{e}(2),{f}(3),{g}(4),{h}(5),{i}(6),{k}(7),{L}(8)) - interpolated curve through points

That should allow me to select the points in the correct sequence. I’m sure there is a way of telling grasshopper to grab items in this pattern (and Ideally restructuring the data), I just don’t know how.

Do you intend to wait for someone who has all your plugins? Or present a file that all of us can see?

See suggestion #3 on this page:

3. Attach minimal versions of all the relevant files

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Hi Joseph,

Never new about the internalize data command before. Thanks.

This copy shouldn’t have any components that require plugins

What copy? No file included in your post.

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Try again. This file is useless.
Not that I’ll be the one to help you… but this is the best way to get help.


I’m Not Sure if I Understand your intention correctly, But I Guess you can overlook the data management complexities and solve your issue with geometrical approach like this: (9.4 KB)

I found that adding an integer slider (24) to the Partition ‘S’ input looks useful?

Have you Consider Flatten the data tree before “join curve” command?

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This looks clumsy to me, more complicated than necessary? (62.2 KB)


Hey guys,

Thank you for the help, and all of the solutions. And Joseph_Oster, I totally forgot that I was moving my data in Elefront components. Sorry about that.

But yeah, Joseph, you totally figured it out. That’s exactly the result I was trying (and failing) to get. Sorry you had to deconstruct the brep’s and start again. I think I’ve just about got my head around your solution and how you shifted the list data. This is a good lesson in managing data in trees.

I’ll try and come up with a less complicated solution and post it. Thank you again for helping me with this. Lots of gratitude to everyone that helped with solutions.

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Dear @Nicholas_Holt you probably didn’t even look at my examples in the first post. The line input is flattened because a branch gathers lines going straight up and not around in a spiral shape just yet. Flattening the tree is the easiest way to do this.

It seems you don’t know much about data trees. Therefore I’d suggest reading the modelab primer.

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In addition to temporary text panels and the Point List component, these are the tools I use to visualize and understand data trees of geometry:
data_tree_tools_2022_Nov3a (46.6 KB)

Recently I added ‘A’ (alpha) inputs and ‘C’ (color) outputs to ColorB and ColorJ but I rarely need them or use them.

They tend to interfere with each other so I often use them one at a time.

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Hi Martin,

Sorry, I did try to flatten the data coming in but it crashed the RelativeItem component and I couldn’t get any data to come through it.

I had previously tried using ‘ListLength’ +1 to get the next item. However, I couldn’t make sense of how the RelativeItem component worked after the list was flattened and there were no branches left in it (i.e. there were no {n} branches to offset).

I am gonna give that ModeLab document a read. I have some sense of how the data is stored, but I don’t fully know what commands to use with what components to navigate my data. This was why I posted to the group, because I was definitely lacking some knopwledge.

Thanks Joseph. This is a great tool set. Definitely helps with visualizing data. Just gotta learn how to navigate it now.

Thanks Again

Flatten here, not the points of course :man_facepalming:

I can’t help wondering if there was useful data tree structure earlier in the process, when the panels were made, that would simplify the spirals? A significant complication was that panels on the innermost ring (at the top) have two points for the spirals instead of only one, like all the rest.