Hi , I really need this guy . isn’t it fixed yet ? https://mcneel.myjetbrains.com/youtrack/issue/RH-10076

Hi @sagkoyeou , Looks like it might get some attention in Rhino 7 - sorry. Just curious, why do you need this? – Dale

Hi Dale Just developing something in grasshopper going about meshes and I haven’t found any solution yet :slight_smile:

What are you trying to do? It may be fairly easy to cook up a method that should work in the meantime…

If there’s rewritten a code that do the inclusion boolean so that may help me a lot , I just need some mesh point inclusion test as booleans output . just simple

It would be helpful for you to post an example of a mesh and point that is failing…that way I can quickly confirm if the reason for its failure is consistent with what I’ve seen in the past.

isPointInsideBug.gh (12.0 KB) List<Point3d> includedPts = new List<Point3d>(); foreach(Point3d pt in array) { bool gooz = iMesh.IsPointInside(pt, 0.0, true); //cull pattern if (gooz) includedPts.Add(pt); }

The method Rhino uses is intersecting a ray with the mesh and counting number of intersections. It shoots a diagonal ray, in the direction (1,1,1). If this ray hits an edge of the mesh rather than a face it tends to fail. You can see this happening in your file if you inflate a bit the bounding box…

Attached is your file with the trick of rotating a bit the mesh before checking. You have points coincident with the boundary. I inflated the bbox by the tolerance amount to keep them in. isPointInsideBug.gh (9.2 KB)

[Capture] I lifted the code for the winding numbers algorithm from the geometry3sharp library and added it at the bottom of your script. It even works with open meshes pretty well. I used the simpler method, which is just a few lines of code, but slow. There’s a faster method also implemented in …

Mesh IsPointInside bug

Rhino Developer

brian (Brian Gillespie) March 24, 2026, 9:59pm 11

RH-10076 is fixed in Rhino WIP

Topic		Replies	Views
Mesh.IsPointInside() failure... workarounds? Scripting	3	711	October 19, 2023
Mesh.IsPointInside() persistent bug Rhino Developer	8	1409	March 24, 2026
IsPointInside - bug Rhino Developer	11	1478	August 16, 2022
IsPointInside of Rhino3dmIO seems to fail completely Rhino Developer	9	1088	July 29, 2020
Mesh point inclusion test reports unexpected result Grasshopper mesh	14	1479	April 28, 2020

Mesh IsPointInside bug

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