XAtlas.Run doesn't work

[Veloctor]

if (input_mesh.PositionsCount != 0)
				ObjLoader.SetMeshPositions(0, input_mesh.Positions, input_mesh.PositionsCount);

			if (input_mesh.NormalsCount != 0)
				ObjLoader.SetMeshNormals(0, input_mesh.Normals, input_mesh.NormalsCount);

			if (input_mesh.TexcoordsCount != 0)
				ObjLoader.SetMeshIndices(0, input_mesh.Indices, input_mesh.IndicesCount);

Why set indices with detection of texcoords count? if I already have texcoords, why should I use this?

			ObjLoader.GetShape(0, out Shape shape);
                        output_mesh = new MeshDes();
			input_mesh.Positions = new float[shape.Mesh.Positions];
			ObjLoader.GetMeshPositions(0, input_mesh.Positions, input_mesh.Positions.Length);
			input_mesh.Normals = new float[shape.Mesh.Normals];
			ObjLoader.GetMeshNormals(0, input_mesh.Normals, input_mesh.Normals.Length);

			input_mesh.Texcoords = new float[shape.Mesh.Texcoords];
			ObjLoader.GetMeshTexcoords(0, input_mesh.Texcoords, input_mesh.Texcoords.Length);

			input_mesh.Indices = new uint[shape.Mesh.Indices];
			ObjLoader.GetMeshIndices(0, input_mesh.Indices, input_mesh.Indices.Length);

Why get mesh by this way? Is it generated mesh?