Rhino 8 : CreateConvexHull3D method bug?

Grasshopper
1

CreateConvexHull3D method returns an incorrect mesh.

Attached GH file with sample Python script including the point set that results in an faulty hull mesh. The resulting hull from the pointset should be octahedral. Note the one face with overlapping geometry.

I would be interested in a fix to the function or in a way to post process the mesh output to fix the hull.

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image1307Ă—948 38.3 KB

incorrect hull.gh (6.8 KB)

Python script:

import Rhino.Geometry as rg
import System
from System.Collections.Generic import List
import clr

Constants

TOLERANCE = 1e-6
ANGLE_TOLERANCE = 0.01

Minimal Convex Hull Function

def create_convex_hull(points):
if len(points) < 4:
print(“Insufficient points for a convex hull.”)
return None

net_points = List[rg.Point3d](points)
hull_facets_ref = clr.Reference[System.Array[System.Array[int]]]()

hull_mesh = rg.Mesh.CreateConvexHull3D(net_points, hull_facets_ref, TOLERANCE, ANGLE_TOLERANCE)

if hull_mesh:
    print("Convex hull mesh created.")
    return hull_mesh
else:
    print("Convex hull generation failed.")
    return None

points = points

hull_mesh = create_convex_hull(points)
if hull_mesh:
print(f"Hull mesh vertices: {hull_mesh.Vertices.Count}“)
print(f"Hull mesh faces: {hull_mesh.Faces.Count}”)

2

Hi @Anton,

Thanks - I’ve logged the issue so a developer can have a look.

https://mcneel.myjetbrains.com/youtrack/issue/RH-85385

In the meantime, use Rhino’s PackageManager command to install RhinoPolyhedra. Then, use it’s QuickHull component.

correct hull.gh (6.3 KB)

– Dale

3

Great, I was not aware of this package. This solves my issue. Still good to get the function checked/updated if need be.

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