measure thickness

[feifeizuo]

Hi, Thank you very much for providing the ray method to calculate the mesh thickness in the computeThicknessAtVertices function. In general, a more accurate method of maximum inscribed sphere (MIS) can also be used to calculate the mesh thickness, refer to the Paper https://www.cad-journal.net/files/vol_13/CAD_13 (2) _2016_199 -207.pdf . At the same time, both the MIS method and the ray method are implemented in the trimesh library. It would be very helpful if the MIS method could be implemented.

thanks

[Grantim]

Hello!

Thanks for the suggestion and the link (unfortunately it is 404, could you please update it). We will research into this and discuss with the team.

[feifeizuo]

this paper : Shrinking sphere: A parallel algorithm for computing the thickness of 3D objects

[Fedr]

Thanks for the suggestion. We have implemented it in MeshLib, see MeshLib\source\MRMesh\MRMeshThickness.h:

/// returns the thickness at each vertex as the diameter of the inscribed sphere
[[nodiscard]] MRMESH_API std::optional<VertScalars> computeInSphereThicknessAtVertices( const Mesh& mesh,
    const InSphereSearchSettings & settings, const ProgressCallback & progress = {} );

Comparison. Ray method:

Maximum inscribed sphere method:

[tobias-scheepers]

Hi @Fedr this looks great. Any chance of exposing this to python also? Are there any downsides to this function as opposed to the original ray-casting method?

[Fedr]

Hi @tobias-scheepers,

Both methods are already exposed to python, please look for computeRayThicknessAtVertices and computeInSphereThicknessAtVertices functions there.

Ray-casting method always returns same or larger value compared to inscribed-sphere method, and ray-casting is typically much faster. And the difference is drastic in peak-like vertices, where inscribed-sphere method returns very small number (where the sphere touches the nearest neighbour vertex). So please select one of the methods based on your need.