view_srep: s-rep viewer

In polykde: Polyspherical Kernel Density Estimation

s-rep viewer

Description

Plots a skeletal representation (s-rep) object based on its three-dimensional base, spokes, and boundary.

Usage

view_srep(
  base,
  dirs,
  bdry,
  radii,
  show_base = TRUE,
  show_base_pt = TRUE,
  show_bdry = TRUE,
  show_bdry_pt = TRUE,
  show_seg = TRUE,
  col_base = "red",
  col_bndy = "blue",
  col_seg = "green",
  static = TRUE,
  texts = NULL,
  cex_base = ifelse(static, 0.5, 6),
  cex_bdry = ifelse(static, 1, 8),
  lwd_seg = ifelse(static, 1, 2),
  cex_texts = 1,
  alpha_base = 0.1,
  alpha_bdry = 0.15,
  r_texts = 1.25,
  alpha_ashape3d_base = NULL,
  alpha_ashape3d_bdry = NULL,
  lit = FALSE,
  ...
)

Arguments

base	base points, a matrix of size c(nx, 3).
dirs	directions of spokes, a matrix of size c(nx, 3) with unit vectors.
bdry	boundary points, a matrix of size c(nx, 3). Optional; computed internally as base + radii * dirs if missing.
radii	radii of spokes, a vector of size nx. Optional; computed internally from base and bdry if missing.
show_base, show_base_pt	show base and base grid? Default to TRUE.
show_bdry, show_bdry_pt	show boundary and boundary grid? Default to TRUE.
show_seg	show segments? Defaults to TRUE.
col_base, col_bndy, col_seg	colors for the base, boundary, and segments. Default to "red", "blue", and "green", respectively.
static	use static (scatterplot3d) or interactive (plot3d) plot? Default to TRUE.
texts	add text labels? If given, it should be a vector of size nx with the labels. Defaults to NULL.
cex_base, cex_bdry	size of the base and boundary points.
lwd_seg	width of the segments.
cex_texts	size of the text labels. Defaults to 1.
alpha_base, alpha_bdry	transparencies for base and boundary. Default to 0.1 and 0.15, respectively.
r_texts	magnification of the radius to separate the text labels. Defaults to 1.25.
alpha_ashape3d_base, alpha_ashape3d_bdry	alpha parameters for ashape3d. Default to NULL.
lit	lit parameter passed to material3d. Defaults to FALSE.
...	further arguments to be passed to plot3d or scatterplot3d.

Value

Invisibly returns NULL. Called for the side effect of producing a static or interactive 3D plot of the s-rep.

References

García-Portugués, E. and Meilán-Vila, A. (2023). Hippocampus shape analysis via skeletal models and kernel smoothing. In Larriba, Y. (Ed.), Statistical Methods at the Forefront of Biomedical Advances, pp. 63–82. Springer, Cham. \Sexpr[results=rd]{tools:::Rd_expr_doi("10.1007/978-3-031-32729-2_4")}

See Also

hippocampus, interp_polysph.

Examples

if (requireNamespace("scatterplot3d", quietly = TRUE)) {
  base <- r_unif_polysph(n = 50, d = 2)
  dirs <- base
  radii <- runif(nrow(base), min = 0.5, max = 1)
  bdry <- base + radii * dirs
  view_srep(base = base, dirs = dirs, bdry = bdry, radii = radii,
            texts = 1:50, xlim = c(-2, 2), ylim = c(-2, 2), zlim = c(-2, 2))
}

polykde documentation built on Nov. 13, 2026, 1:08 a.m.