Fill a volume cube based on water-tight surface

Create a cube volume (256 'voxels' on each margin), fill in the 'voxels' that are inside of the surface.

Usage

fill_surface(
  surface,
  inflate = 0,
  IJK2RAS = NULL,
  preview = FALSE,
  preview_frame = 128
)

Arguments

surface

a surface mesh, can be mesh objects from rgl or freesurferformats packages

inflate

amount of 'voxels' to inflate on the final result; must be a non-negative integer. A zero inflate value means the resulting volume is tightly close to the surface

IJK2RAS

volume 'IJK' (zero-indexed coordinate index) to 'tkrRAS' transform, default is automatically determined leave it `NULL` if you don't know how to set it

preview

whether to preview the results; default is false

preview_frame

integer from 1 to 256 the depth frame used to generate preview.

Value

A list containing the filled volume and parameters used to generate the volume

Details

This function creates a volume (256 on each margin) and fill in the volume from a surface mesh. The surface vertex points will be embedded into the volume first. These points may not be connected together, hence for each 'voxel', a cube patch will be applied to grow the volume. Then, the volume will be bucket-filled from a corner, forming a negated mask of "outside-of-surface" area. The inverted bucket-filled volume is then shrunk so the mask boundary tightly fits the surface

Author

Zhengjia Wang

Examples

if(interactive()) { # takes > 5s to run example

# Generate a sphere
surface <- vcg_sphere()
surface$vb[1:3, ] <- surface$vb[1:3, ] * 50

fill_surface(surface, preview = TRUE)

}