PlaneIntersectionCache
ReferencesData that Intersection.GeometryPlane(GeometryBase, Plane, double, bool, bool, bool, RhinoDoc, Transform, PlaneIntersectionCache, CancellationToken, Curve[], Point3d[]) computes from the geometry alone, kept between calls: the mesh intersection data of a mesh, and the Brep a SubD, Extrusion, Surface or BrepFace converts to. Reuse one cache for many planes through the same geometry, such as a contour stack.
Remarks: Entries are keyed by the native geometry. The cache keeps each geometry it is used with alive until Clear() or Dispose(), so a new object cannot take over the entry of a collected one. Call Clear() when a geometry used with the cache, or an instance definition it references, is changed in place; not while the cache is in use. One cache can be used from several threads at the same time.