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The data is copied from the output cell of my original data.

pts={{25.3232,93.3884,7.90173},{25.3232,93.3884,15.6372},{25.3232,101.869,15.6372},{25.3232,101.869,7.90173},{25.6231,93.3884,7.90173},{25.6231,101.869,7.90173},{25.6231,93.3884,15.6372},{25.6231,101.869,15.6372},{25.6231,111.391,15.6372},{25.6231,111.391,7.90173},{25.923,101.869,7.90173},{25.923,111.391,7.90173},{25.923,101.869,15.6372},{25.923,111.391,15.6372}};

meshTest=ConvexHullMesh@pts


RegionResize[meshTest,10]

works properly

But in my original raw mesh, it works improperly.

ptsOrignal={{25.323178174128376`,93.38837529045934`,7.90172510421934`},{25.323178174128376`,93.38837330947786`,15.637175854060626`},{25.323178174128376`,101.86875495322009`,15.637176769628931`},{25.323178174128376`,101.86875627387441`,7.901726019787645`},{25.623105100248882`,93.38837529045934`,7.90172510421934`},{25.623105100248882`,101.86875627387441`,7.901726019787645`},{25.623105100248882`,93.38837330947786`,15.637175854060626`},{25.623105100248882`,101.86875495322009`,15.637176769628931`},{25.623105100248882`,111.39085617922113`,15.637177685197237`},{25.623105100248882`,111.39085882052977`,7.901727850924257`},{25.923034314647705`,101.86875627387441`,7.901726019787645`},{25.923034314647705`,111.39085882052977`,7.901727850924257`},{25.923034314647705`,101.86875495322009`,15.637176769628931`},{25.923034314647705`,111.39085617922113`,15.637177685197237`}};

meshTest=ConvexHullMesh@ptsOrignal


RegionResize[meshTest,10]

So is it a bug?

=== Since RegionResize is probably implemented by TransformedRegion.

This problem also happen in TransformedRegion.

TransformedRegion[meshTest,ScalingTransform[{0.01,2,0.9}]] Works Fine

TransformedRegion[meshTest,ScalingTransform[{0.01,2,0.8}]]

enter image description here

enter image description here

HyperGroups
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  • Strange. Remove this point and the error goes away: {25.623105100248882`, 101.86875495322009`, 15.637176769628931`} – flinty Jun 11 '20 at 11:53

1 Answers1

3

Using FindMeshDefects shows that the second example produces "tiny faces". You can use RepairMesh as clean up step to remove such errors like so:

meshTest = ConvexHullMesh@ptsOrignal
FindMeshDefects[meshTest]
meshTest = RepairMesh[meshTest];
RegionResize[meshTest, 10]

Repaired Mesh

Tim Laska
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  • Thanks for your digging. The bad thing is RepairMesh will sometimes broke the shape of the model. – HyperGroups Jul 10 '20 at 07:23
  • TransformedRegion[mesh,ScalingTransform[{0.01,2,0.9}]] works fine. TransformedRegion[mesh,ScalingTransform[{0.01,2,0.8}]] failed – HyperGroups Jul 10 '20 at 07:33
  • @HyperGroups They both worked on my machine 12.1.1 for Microsoft Windows (64-bit) (June 19, 2020) after I repaired the mesh. If you want more options to repair the mesh, have you looked at MeshLab? I posted an answer 214907 on how to decimate a mesh from Mathematica calling MeshLab. – Tim Laska Jul 10 '20 at 16:09