// between points
MapPoint pt1 = MapPointBuilderEx.CreateMapPoint(1, 1, 1);
MapPoint pt2 = MapPointBuilderEx.CreateMapPoint(2, 2, 2);
MapPoint pt3 = MapPointBuilderEx.CreateMapPoint(10, 2, 1);
// pt1 to pt2
double d = GeometryEngine.Instance.Distance3D(pt1, pt2); // d = Math.Sqrt(3)
// pt1 to pt3
d = GeometryEngine.Instance.Distance3D(pt1, pt3); // d = Math.Sqrt(82)
// pt2 to pt3
d = GeometryEngine.Instance.Distance3D(pt2, pt3); // d = Math.Sqrt(65)
// intersecting lines
List<MapPoint> list = new List<MapPoint>();
list.Add(MapPointBuilderEx.CreateMapPoint(1.0, 1.0, 1.0));
list.Add(MapPointBuilderEx.CreateMapPoint(3.0, 3.0, 1.0));
list.Add(MapPointBuilderEx.CreateMapPoint(5.0, 1.0, 1.0));
Polyline line1 = PolylineBuilderEx.CreatePolyline(list);
List<MapPoint> list2 = new List<MapPoint>();
list2.Add(MapPointBuilderEx.CreateMapPoint(1.0, 3.0, 1.0));
list2.Add(MapPointBuilderEx.CreateMapPoint(3.0, 1.0, 1.0));
list2.Add(MapPointBuilderEx.CreateMapPoint(5.0, 3.0, 1.0));
Polyline line2 = PolylineBuilderEx.CreatePolyline(list2);
bool intersects = GeometryEngine.Instance.Intersects(line1, line2); // intersects = true
d = GeometryEngine.Instance.Distance3D(line1, line2); // d = 0 (distance is 0 when geomtries intersect)