ArcGIS Pro 3.4 API Reference Guide
ArcGIS.Core.Geometry Namespace / GeometryEngine Class / Length3D Method
The input geometry.
Example Version

Length3D Method (GeometryEngine)
Gets the 3D length for a specified geometry.
Syntax
public double Length3D( 
   Geometry geometry
)

Parameters

geometry
The input geometry.

Return Value

The calculated length in the same units as the geometry's spatial reference unit. If the geometry is empty, then zero is returned.
Exceptions
ExceptionDescription
Geometry is null.
The method is not implemented for GeometryBag or Multipatch.
The geometry is not Z-Aware.
Cannot do 3D operations on curve segments.
Geometry is not a polyline or polygon.
Remarks
The geometry must be Z-Aware or else an exception is thrown.
Example
Determine Length, Length3D of line
MapPoint c1 = MapPointBuilderEx.CreateMapPoint(1, 2, 3);
MapPoint c2 = MapPointBuilderEx.CreateMapPoint(4, 2, 4);

// line segment
LineSegment line = LineBuilderEx.CreateLineSegment(c1, c2);
double len = line.Length;     // = 3
double len3D = line.Length3D;   // = Math.Sqrt(10)

// polyline
Polyline p = PolylineBuilderEx.CreatePolyline(line);
double p_len = p.Length;        // = len = 3
double p_len3D = p.Length3D;    // = len3D = Math.Sqrt(10)

double ge_len = GeometryEngine.Instance.Length(p);      // = p_len = len = 3
double ge_len3d = GeometryEngine.Instance.Length3D(p);    // = p_len3D = len3D = Math.Sqrt(10)
Requirements

Target Platforms: Windows 11, Windows 10

ArcGIS Pro version: 3 or higher.
See Also