DNE | R Documentation |

A function that calculates Dirichlet normal energy following the method of Bunn et al. (2011) Comparing Dirichlet normal surface energy of tooth crowns, a new technique of molar shape quantification for dietary inference, with previous methods in isolation and in combination. Am J Phys Anthropol 145:247-261 doi: 10.1002 ajpa.21489

DNE(plyFile, outliers = 0.1, kappa = 0, BoundaryDiscard = "Vertex", oex = "c")

`plyFile` |
An object of classes 'mesh3d' and 'shape3d' with calculated normals |

`outliers` |
The percentile of Dirichlet energy density values to be excluded defaults to top 0.1 percent |

`kappa` |
An integer value of mean curvature to define concave vs convex faces |

`BoundaryDiscard` |
String indicating how to handle the exclusion of boundary faces. Default of Vertex excludes faces which have at least 1 vertex on the boundary |

`oex` |
String indicating outlier exclusion principle. Defaults to 'c', which
combines all convex and concave faces and removes the percentage of outliers
defined by |

The function requires an object created by reading in a ply file.

Dirichlet normal energy is calculated on meshes that represent specimen surfaces and have already been simplified and pre-smoothed in a 3D data editing program.

In the default settings, the function seeks to discard boundary faces. This can be
changed by adjusting the `BoundaryDiscard`

argument to 'None' which will not discard
any faces on the boundary. Further, there are two ways of excluding boundary faces.
Either if they have a leg on the boundary by setting `BoundaryDiscard='Leg'`

or by
excluding any face which has a vertex on the boundary with `BoundaryDiscard='Vertex'`

.
The function defaults to remove the top 0.1 percent of calculated energy densities as
outliers. Mesh orientation does not affect this calculation.

Faces are labeled as concave or convex on the basis of the `kappa`

value, which
defaults to 0. Each face is assigned a `kappa`

value, which describes the the localized
degree of convergence or divergence among the three vertex normals on each face.
Faces with positive `kappa`

values have vertex normals that are divergent. Faces with
negative `kappa`

values possess vertex normals that are convergent. Users can adjust
the `kappa`

value to redefine areas of the tooth assigned to the convex or concave bin.

The mode of Outlier exclusion can be modified with the `oex`

argument. The default,
`oex='c'`

considers the Dirichlet energy density values of all faces on the surface and
removes those in the top percentile defined by `outliers`

, regardless of the convexity
or concavity bins. The alternative, `oex='s'`

, divides the surface into concave and
convex portions, then removes the percentile defined by `outliers`

from each of
these subsets before calculating total surface DNE.

DNE_output <- DNE(Tooth) summary(DNE_output)

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