mesh.slice.intersection: Compute intersection of a triangular surface mesh with an...

In fsbrain: Managing and Visualizing Brain Surface Data

Compute intersection of a triangular surface mesh with an axis-aligned plane.

Description

For a given axis and coordinate, finds all triangles that straddle the plane and computes the line segment where each crossing triangle intersects the plane. The input surface must have vertices in the same coordinate space as the slice plane definition (typically 0-based CRS).

Usage

mesh.slice.intersection(surface, axis, slice_crs_coord)

Arguments

surface	an fs.surface instance with vertices in CRS space (0-based), as produced by mesh.ras2crs.
axis	integer, 1, 2, or 3. The axis perpendicular to the slice plane (1=sagittal, 2=coronal, 3=axial in CRS convention).
slice_crs_coord	numeric scalar, the coordinate along axis where the slice plane is located. In CRS space (0-based).

Value

a list of 2×2 numeric matrices. Each matrix represents one line segment with rows ⁠[start, end]⁠ and columns ⁠[axis_val_1, axis_val_2]⁠ giving the coordinates in the two axes orthogonal to the slice axis, in 0-based CRS units. Returns an empty list if no triangles intersect the plane.

fsbrain documentation built on Aug. 23, 2026, 5:06 p.m.