intersectSystem: Intersection in 3D
In unfoldr: Stereological Unfolding for Spheroidal Particles

Description Usage Arguments Details Value Author(s) Examples

Intersect a system of spheres, spheroids or spherocylinders by a plane

1	intersectSystem(S, d, n = c(0, 1, 0), intern = FALSE, pl = 0)

`S`	list of spheres, spheroids or spherocylinders, see `simPoissonSystem`
`d`	distance of the the box-aligned intersecting plane from the origin
`n`	normal vector which defines the intersecting plane
`intern`	logical, `FALSE` (default), return all section profiles otherwise only those which have their centers inside the corresponding intersection window (if the intersected system had been simulated using exact simulation this makes sense)
`pl`	integer, `pl=0` (default), for no verbose output and otherwise a full specification list of section profiles in case of sphere and spheroid intersections

The function intersects a given (Poisson) system made of spheres, spheroids or cylinders as grains by a plane defined by a normal vector, e.g. n=c(0,1,0), perpendicular to one of the bounding planes of the simulation box. For a print level pl>=0 some verbose output is given. Also it sets the type of return value. In case of spheroid intersections, setting pl=10, leads to a short version of the full specification return list of section profiles with elements named A (major semi-axis), C (minor semi-axis), S (the shape factor as the ratio of these two) and phi as the angle in the intersecting plane between [0,2π] w.r.t. the 'x' axis. Otherwise additional components are returned such as the ellipse's rotation matrix, also named A, the center point center and a constant type=10 (defining the object of full ellipses among other types of intersection objects) of the section profiles. For sphere intersections only a numeric vector of disc radii are returned as a short version of return values.

For spheroid intersections the function returns a list of size, shape and angle of section profiles or a short version of it; for sphere intersections either radii or lists containing the centers of discs and the object number.

M. Baaske

 box <- list("xrange"=c(0,5),"yrange"=c(0,5),"zrange"=c(0,5))
 
 # constant size-shape orientation distribution (spheroids)
 theta <- list("size"=list(0.1),"shape"=list(0.5), "orientation"=list("kappa"=10))

 S <- simPoissonSystem(theta,lam=100,box=box,type="prolate",pl=1)
 
 # return short version of section profiles
 sp <- intersectSystem(S, 2.5, pl=10)