//// This code is part of Document Solutions for PDF .NET demos.// Copyright (c) MESCIUS inc. All rights reserved.//using System.IO;using System.Drawing;using GrapeCity.Documents.Pdf;using GrapeCity.Documents.Pdf.Annotations;using DsPdfWeb.Demos.Common;
namespace DsPdfWeb.Demos.Basics{    // This demo shows how to embed an interactive 3D model in a PDF using Annotation3D.    public class Annotation3D    {        public int CreatePDF(Stream stream)        {            var doc = new GcPdfDocument();            var page = doc.NewPage();
            var rc = Util.AddNote(                "The rectangle below is a Model3DAnnotation containing a 3D model. " +                "It activates automatically when this page becomes visible, but can only be viewed interactively " +                "in a PDF reader with native 3D support, such as Adobe Acrobat/Reader.", page);
            // Load the 3D model (U3D format):            var modelPath = Path.Combine("Resources", "3DModels", "plane64x64_base.u3d");            using var modelStream = File.OpenRead(modelPath);
            // Add a 3D annotation showing the model, activated when the page becomes visible:            var m3d = new Model3DAnnotation            {                Stream = new Model3DStream(modelStream, Model3DStreamFormat.U3D),                ActivationCondition = Model3DActivationCondition.PageBecomesVisible,                DeactivationCondition = Model3DDeactivationCondition.PageBecomesInvisible,                Page = page,                Rect = new RectangleF(rc.X, rc.Bottom + 18, 72 * 5, 72 * 4)            };
            doc.Save(stream);            return doc.Pages.Count;        }    }}