Quan_Li
March 16, 2026, 3:27am
1
IsoCurve bug.gh (19.3 KB)
I got the surface from this post.
Hello everyone,
I am currently working on a parametric design project in Grasshopper where I am trying to generate a personalized crutch handle based on a hand pressure map.
My workflow is currently the following:
I start from a hand pressure image (black/white map)
I use an image sampler to extract grayscale values
These values are mapped onto a cylindrical handle surface
I generate a grid of points on the handle surface and use the sampled values to displace those points
This …
Might related:
[Bug?] Trimmed surface’s Isocurves missing at the seam position - Grasshopper - McNeel Forum
Quan_Li
March 16, 2026, 1:09pm
2
Is this a bug? Where are the extra lines and curve come from?
Not the same thing, extract iso curve seems a bug but there are some extrapolation possible on surface
Dear community
I tried some plugins to put hexagons on a surface with a seam.
I tried lunchbox, ngon. I didn’t try Paneling tool. These tools have problems or the seams (lunchbox, or too much points (polyline with 9 points for ngon plugin), not hexagons at the ends, or too much distorsion …
As I need quite nice hexagons I developed a little tool 2 hours work).
You just have to put the number of hexagons on a ring and say where is the seam (U or V).
[image]
Did I miss an existing tool ?
M…
Quan_Li
March 16, 2026, 1:42pm
4
SAME BUG.gh (33.1 KB)
I guess this is the similar bug solved before. It’s like zombie come back alive and never die…
@kike
Iso Curve , like Iso Trim only works on the untrimmed surfaces. Right now the bug you are seing is that Iso Curve is including the {0,0} V curve because it is not being registered as “within” the domain between the untrimmed surface edge and trimmed surface. You can see all the other V curves being excluded from the empty branches:
The “extra” lines are the U curves, one for each UV coordinate. The only way to fix this is to rebuild as an untrimmed surface.
Quan_Li
March 17, 2026, 2:23am
6
Sorry, I showed the wrong reference. I think it got fixed, but now it returns.
Hi @Quan_Li ,
This is fixed on next 8.20 RC.
Quan_Li
March 17, 2026, 2:28am
7
The 20th guy should not be here
kike
March 17, 2026, 10:46am
8
Hi @Quan_Li ,
You are tight is a bug on the Iso Curve component.
brian
April 14, 2026, 11:41pm
9
