Iterating through i + 1 selection; offsetting curve division points

I have a list of 6 curves generated from isotrimming a surface.

I am trying to select the i and i+1 curve, with n being the number of curves. (see green)

Each set of curves is to be subdivided, with each successive set offsetting the location of the curve division points, to create a running pattern of divisions (see blue)

These are two separate questions but I am showing the intent for context.

I am able to select one grouping of (i, i+1) at a time:

I’m not sure how to create a list of all the groupings.

I think I am clear on how to approach the offsetting of curve division points, once I have the groupings. I will use a series to move the division points along the curves.

curve groupings internalized.gh (12.1 KB)

Thanks!

Sounds like you’re looking for the relative item component

This is exactly what Relative Item(s) is for. BRB with a quick solution

EDIT: Sorry, no I won’t - family duties call!

I ended up not using relative item at all, but instead stayed in surface land and divided by domains. I am assuming that Surfaces are more useful than lists of lines (you could always Brep Edges if you need lines). Given that you said you generated the source curves with isolines, this file contains redundant remaking of the source surface, but you should be able to refactor it to suit. Let me know if you run into trouble.

Surface Groupings.gh (19.8 KB)

Further thought: There’s an option to use the same list of parameters for all curves so you don’t get distortion of the pattern in the middle. Downside is each strip will contain tiles of differing widths.

Before

After:

Surface Groupings aligned.gh (21.8 KB)

Not sure this works the way you intended to do it but I was wondering about keeping subdivision lines ‘perpendicular’ and tried this first:
curve groupings internalized_0.gh (46.7 KB)


If not it could be more basic:
curve groupings internalized_1.gh (38.9 KB)


I also started off going down the “keep them perpendicular” route, but found the offset going in and out of phase as the guide curves bend around, just as you have:

You could use the perpendicular point as the source for the next offset, but the errors would compound and you’d end up with terrible distortion.

:thinking:

You’re right - thought I could fake it a bit (incrementing curve length evaluation) but it’ll look like bricks :-1:
curve groupings internalized_0b.gh (31.5 KB)

Thank you, this is very helpful, I am trying to open Surface Groupings aligned.gh but don’t seem to see anything in my Rhino viewport. I would like to check out the file and see if I can implement the curve length evaluation described by @René_Corella, as this brick-like result is actually very close to what I am going for.

Apologies, I forgot to internalise!

Surface Groupings aligned.gh (24.5 KB)