Ref to marked area and files attached
GH:
cull.gh (44.6 KB)
IMG:
- Why are the indies not accepting the syntax demonstrated in the image? Is it possible to approach this problem using {} () format - NOT ( 0 to…) or using Series component?
I understand the answer provided by an agentic ChatBot. So there’s no way to work around the way I intended?
Short answer: that syntax isn’t valid in Grasshopper. Cull Index expects actual integers in its I (Indices) input, not a formula in the panel. The fix is to generate a proper list of indices and plug that into I.
What’s going on
- Cull Index’s I input takes integers; it doesn’t parse expressions like “-[*](1 to ?)” from a panel. It just sees a single text value and fails. Official docs show I’s param type as “Integer” (meaning a list of integers).【turn5fetch0】
How to do what you wanted (a range of indices)
- If you wanted “all indices from 1 up to N” to be removed, generate that list and feed it into I. Two easy ways:
1) With a panel (simple, explicit)
- Double-click a Panel and type the indices on separate lines, e.g.:
1
2
3
4
5
- Set the Panel’s type to “Data” (right-click the panel > Data), then plug it into Cull Index > I.
1) With components (dynamic, recommended)
- Use Series to make an integer list and connect it to Cull Index > I:
• Series > S (Start) = 1
• N (Step) = 1
• C (Count) = however many indices you want to remove (or compute it from List Length − 1)
- Series generates [1, 2, 3, …, C] which is exactly the kind of integer list Cull Index expects.
If you meant a reverse/“down to” range
- Grasshopper panels don’t support “1 to N” or “N to 1” syntax at all. Use components:
- To cull indices from N down to 1 (e.g., 10..1), make a Series from 1 to N and then Reverse List before plugging into Cull Index > I.
Note about negative indices
- Cull Index expects positive indices (0-based). Negative-index syntax (like Python’s -1 for last item) isn’t supported in Cull Index. Use explicit positive indices or compute them from the list length instead.
So, remove the formula from the panel, give Cull Index an actual list of integers, and it will work.
- Why does it must use a group component? Isn’t a branch considered a ‘group?’ At the very least, clicking the voronoi component in this case selects all objects, indicating that it is a group.
