Camera Class

public class Camera

// Copyright 2017 Esri.
// 
// Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License.
// You may obtain a copy of the License at: http://www.apache.org/licenses/LICENSE-2.0
// 
// Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an
// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific
// language governing permissions and limitations under the License.

using Android.App;
using Android.OS;
using Android.Widget;
using Esri.ArcGISRuntime.Mapping;
using Esri.ArcGISRuntime.UI.Controls;
using System;
using Esri.ArcGISRuntime.Geometry;

namespace ArcGISRuntime.Samples.SceneLayerUrl
{
    [Activity (ConfigurationChanges=Android.Content.PM.ConfigChanges.Orientation | Android.Content.PM.ConfigChanges.ScreenSize)]
    [ArcGISRuntime.Samples.Shared.Attributes.Sample(
        "ArcGIS scene layer (URL)",
        "Layers",
        "Display an ArcGIS Scene layer from a service.",
        "")]
    public class SceneLayerUrl : Activity
    {
        // Create a new SceneView control
        private readonly SceneView _mySceneView = new SceneView();

        // URL for a service to use as an elevation source.
        private readonly Uri _elevationSourceUrl = new Uri(
            "https://elevation3d.arcgis.com/arcgis/rest/services/WorldElevation3D/Terrain3D/ImageServer");

        // URL for the scene layer.
        private readonly Uri _serviceUri = new Uri(
            "https://tiles.arcgis.com/tiles/P3ePLMYs2RVChkJx/arcgis/rest/services/Buildings_Portland/SceneServer");

        protected override void OnCreate(Bundle bundle)
        {
            base.OnCreate(bundle);

            Title = "ArcGIS scene layer (URL)";

            CreateLayout();
            Initialize();
        }

        private async void Initialize()
        {
            // Create new Scene.
            Scene myScene = new Scene {Basemap = Basemap.CreateImagery()};

            // Create and add an elevation source for the Scene.
            ArcGISTiledElevationSource elevationSrc = new ArcGISTiledElevationSource(_elevationSourceUrl);
            myScene.BaseSurface.ElevationSources.Add(elevationSrc);

            // Create new scene layer from the URL.
            ArcGISSceneLayer sceneLayer = new ArcGISSceneLayer(_serviceUri);

            // Add created layer to the operational layers collection.
            myScene.OperationalLayers.Add(sceneLayer);

            try
            {
                // Load the layer.
                await sceneLayer.LoadAsync();

                // Get the center of the scene layer.
                MapPoint center = (MapPoint)GeometryEngine.Project(sceneLayer.FullExtent.GetCenter(), SpatialReferences.Wgs84);

                // Create a camera with coordinates showing layer data.
                Camera camera = new Camera(center.Y, center.X, 225, 220, 80, 0);

                // Assign the Scene to the SceneView.
                _mySceneView.Scene = myScene;

                // Set view point of scene view using camera.
                await _mySceneView.SetViewpointCameraAsync(camera);
            }
            catch (Exception e)
            {
                new AlertDialog.Builder(this).SetMessage(e.ToString()).SetTitle("Error").Show();
            }
        }

        private void CreateLayout()
        {
            // Create a new vertical layout for the app.
            LinearLayout layout = new LinearLayout(this) { Orientation = Orientation.Vertical };

            // Add the scene view to the layout.
            layout.AddView(_mySceneView);

            // Show the layout in the app.
            SetContentView(layout);
        }
    }
}

// Copyright 2019 Esri.
// 
// Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License.
// You may obtain a copy of the License at: http://www.apache.org/licenses/LICENSE-2.0
// 
// Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an 
// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific 
// language governing permissions and limitations under the License.

using System;
using Esri.ArcGISRuntime.Geometry;
using Esri.ArcGISRuntime.Mapping;
using Esri.ArcGISRuntime.Symbology;
using Esri.ArcGISRuntime.UI;
using Xamarin.Forms;
using Color = System.Drawing.Color;

namespace ArcGISRuntimeXamarin.Samples.SceneSymbols
{
    [ArcGISRuntime.Samples.Shared.Attributes.Sample(
        "Scene symbols",
        "Symbology",
        "Show various kinds of 3D symbols in a scene.",
        "",
        "Scenes", "Symbols", "Graphics", "graphics overlay", "3D", "cone", "cylinder", "tube", "sphere", "diamond", "tetrahedron")]
    public partial class SceneSymbols : ContentPage
    {
        private readonly string _elevationServiceUrl = "http://elevation3d.arcgis.com/arcgis/rest/services/WorldElevation3D/Terrain3D/ImageServer";

        public SceneSymbols()
        {
            Title = "Scene symbols";
            InitializeComponent();
            Initialize();
        }

        private void Initialize()
        {
            // Configure the scene with an imagery basemap.
            MySceneView.Scene = new Scene(Basemap.CreateImagery());

            // Add a surface to the scene for elevation.
            ArcGISTiledElevationSource elevationSource = new ArcGISTiledElevationSource(new Uri(_elevationServiceUrl));
            Surface elevationSurface = new Surface();
            elevationSurface.ElevationSources.Add(elevationSource);
            MySceneView.Scene.BaseSurface = elevationSurface;

            // Create the graphics overlay.
            GraphicsOverlay overlay = new GraphicsOverlay();

            // Set the surface placement mode for the overlay.
            overlay.SceneProperties.SurfacePlacement = SurfacePlacement.Absolute;

            // Create a graphic for each symbol type and add it to the scene.
            int index = 0;
            Color[] colors = {Color.Red, Color.Green, Color.Blue, Color.Purple, Color.Turquoise, Color.White};
            Array symbolStyles = Enum.GetValues(typeof(SimpleMarkerSceneSymbolStyle));
            foreach (SimpleMarkerSceneSymbolStyle symbolStyle in symbolStyles)
            {
                // Create the symbol.
                SimpleMarkerSceneSymbol symbol = new SimpleMarkerSceneSymbol(symbolStyle, colors[index], 200, 200, 200, SceneSymbolAnchorPosition.Center);

                // Offset each symbol so that they aren't in the same spot.
                double positionOffset = 0.01 * index;
                MapPoint point = new MapPoint(44.975 + positionOffset, 29, 500, SpatialReferences.Wgs84);

                // Create the graphic from the geometry and the symbol.
                Graphic item = new Graphic(point, symbol);

                // Add the graphic to the overlay.
                overlay.Graphics.Add(item);

                // Increment the index.
                index++;
            }

            // Show the graphics overlay in the scene.
            MySceneView.GraphicsOverlays.Add(overlay);

            // Set the initial viewpoint.
            Camera initalViewpoint = new Camera(28.9672, 44.9858, 2495, 12, 53, 0);
            MySceneView.SetViewpointCamera(initalViewpoint);
        }
    }
}

<?xml version="1.0" encoding="utf-8" ?>
<ContentPage xmlns="http://xamarin.com/schemas/2014/forms"
             xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"             
             xmlns:esriUI="clr-namespace:Esri.ArcGISRuntime.Xamarin.Forms;assembly=Esri.ArcGISRuntime.Xamarin.Forms"
             x:Class="ArcGISRuntimeXamarin.Samples.SceneSymbols.SceneSymbols">
  <Grid>
    <esriUI:SceneView x:Name="MySceneView"/>
  </Grid>
</ContentPage>