Sample a surface mesh uniformly

Usage

vcg_uniform_remesh(
  x,
  voxel_size = NULL,
  offset = 0,
  discretize = FALSE,
  multi_sample = FALSE,
  absolute_distance = FALSE,
  merge_clost = FALSE,
  verbose = TRUE
)

Arguments

x: surface
voxel_size: 'voxel' size for space 'discretization'
offset: offset position shift of the new surface from the input
discretize: whether to use step function(TRUE) instead of linear interpolation (FALSE) to calculate the position of the intersected edge of the marching cube; default is FALSE
multi_sample: whether to calculate multiple samples for more accurate results (at the expense of more computing time) to remove artifacts; default is FALSE
absolute_distance: whether an unsigned distance field should be computed. When set to TRUE, non-zero offsets is to be set, and double-surfaces will be built around the original surface, like a sandwich.
merge_clost: whether to merge close vertices; default is TRUE
verbose: whether to verbose the progress; default is TRUE

Value

A triangular mesh of class 'mesh3d'

Coercing Surface Inputs

The surface objects are converted to 'mesh3d' object before applying further calculations.

When surface is a surface ieegio object, the returned mesh3d$vb contains vertices that have been left-multiplied by surface$geometry$transforms[[1]] (the first transform stored in the geometry, typically the ScannerAnat or voxel-to-world transform).

Breaking change: Earlier versions (before 0.2.6) of ravetools returned the raw surface$geometry$vertices without applying any transform, so downstream code often multiplied by surface$geometry$transforms[[1]] (or an equivalent) manually before working in world space. Such code will now double apply the transform and produce incorrect coordinates. If you previously applied a transform from surface$geometry$transforms by hand after calling a ravetools mesh function on an 'ieegio_surface', remove that manual step.

Surfaces with an empty or missing geometry$transforms list (for example, surfaces produced by ieegio's volume_to_surface, which stores an identity transform) are unaffected.

If geometry$transforms contains multiple transforms targeting different coordinate spaces, only the first one is used. Callers that need a specific target space should select and apply that transform themselves before calling ravetools mesh functions.

Examples


sphere <- vcg_sphere()
mesh <- vcg_uniform_remesh(sphere, voxel_size = 0.45)
#> Resampling mesh using a volume of 5 x 5 x 5
#>   VoxelSize is 0.450000, offset is 0.000000
#>   Mesh Box is 2.000000 2.000000 2.000000

if(is_not_cran()) {

rgl_view({

  rgl_call("mfrow3d", 1, 2)

  rgl_call("title3d", "Input")
  rgl_call("wire3d", sphere, col = 2)
  rgl_call("next3d")

  rgl_call("title3d", "Re-meshed to 0.1mm edge distance")
  rgl_call("wire3d", mesh, col = 3)
})

}
#> Package `rgl` is not installed. Please install `rgl` to use this function.
#> Error in loadNamespace(name): there is no package called ‘rgl’