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As the title describes, specifically, simple code below

ConvexHullMesh[RandomReal[1, {10, 2}]]["Centroid"]

returns an error in V. 12.2, but it worked in V. 12.1.1 as far as I remember

BoundaryMeshRegion::unsupported

Is it a bug introduced by the new version? Or is there another way to get the centroid?

Update

I just find it that not only "Centroid", but also extractions of other "Properites" fail; except for "BoundaryPolygons".

Update 2

To make this problem more understandable, let me make some modifications to the code.

mesh = ConvexHullMesh[RandomReal[1, {10, 2}]];
mesh["Properties"]

This would return a long List of strings as the properties mesh has. And then

mesh[str]

would return something, at least without any error message, where str is arbitrary one of the elements of the aforementioned property List; very much like OOP (objective-oriented programming). And that is what would happen in former versions like V. 12.1.1.

However now in V. 12.2, mesh["Centroid"] fails, even though "Centroid" can be found in that property List of mesh.

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    $\begingroup$ RegionCentroid[ConvexHullMesh[RandomReal[1, {10, 2}]]] ? $\endgroup$
    – cvgmt
    Commented Dec 25, 2020 at 8:56
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    $\begingroup$ @cvgmt Thx very much, it works for the data extraction. But it only solves half of the problem. I doubt that something is wrong with BoundaryMeshRegion in the new version, isn't it? $\endgroup$
    – Αλέξανδρος Ζεγγ
    Commented Dec 25, 2020 at 9:00
  • $\begingroup$ MeshPrimitives@ConvexHullMesh[RandomReal[1, {10, 2}]] ? What is the "Properites" ？ $\endgroup$
    – cvgmt
    Commented Dec 25, 2020 at 9:46
  • $\begingroup$ @cvgmt Plz see my Update 2. $\endgroup$
    – Αλέξανδρος Ζεγγ
    Commented Dec 25, 2020 at 9:55
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    $\begingroup$ Perhaps we need to be reminded that these properties are actually undocumented stuff, so there is no guarantee that they should still work in future versions. $\endgroup$
    – J. M.'s missing motivation ♦
    Commented Dec 26, 2020 at 14:02

1 Answer 1

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Accessing properties of BoundaryMeshRegion that way was undocumented and therefore might not work anymore in 12.2.

A somewhat documented way is the AnnotationValue approach. Eg.

AnnotationValue[{ConvexHullMesh[RandomReal[1, {10, 2}]], 1}, MeshCellMeasure]

But this doesn't work for all properties either (also see Possible Issues section). In that case Centroid is not working.

What is still working is this also undocumented approach:

mesh = Graphics`Region`ToMeshObject[ConvexHullMesh[RandomReal[1, {10, 2}]]];
mesh["Centroid"]
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