加载完TIN数据后，需要在三维物体上描绘细节，即纹理；建立DEM表面点与纹理空间点的关系，即纹理映射。叠加影像数据就是把影像看作纹理，将其贴在地形表面，让其具有地形起伏的三维效果。

这里与GlobeControl下三维场景的构建有所不同，在前面的博文中我们提到过，globe下图层主要有三种类型：Floating、Draped、Elevation（浮动、叠加和高程图层），即只需要设置图层的属性即可，叠加图层与浮动图层从高程图层获取高程值。SceneControl中实现影像的叠加，参照ArcScene中的操作：“右键”——>“属性”——>“基本高度”——>“从表面获取的高程”，设置为浮动在自定义表面。

这里主要使用I3DProperties接口，代码如下：

                ISceneGraph pSceneGraph = axSceneControl1.SceneGraph;
                IScene pScene = pSceneGraph.Scene;
                ITinLayer pTinLayer = null;
                IRasterLayer pRasterlayer = null;
                //获取TIN、DOM
                for (int i = 0;i < pScene.LayerCount;i++)
                {
                    ILayer pLayer = pScene.get_Layer(i);
                    if (pLayer is ITinLayer)
                    {
                        pTinLayer = pLayer as ITinLayer;
                    }
                    if (pLayer is IRasterLayer)
                    {
                        pRasterlayer = pLayer as IRasterLayer;
                    }

                }
                //设置3D属性
                ITinAdvanced tinAdvanced = pTinLayer.Dataset as ITinAdvanced;
                ISurface surface = tinAdvanced.Surface;

                ILayerExtensions layerExtensions = pRasterlayer as ILayerExtensions;
                I3DProperties p3DProperties = null;

                for (int i = 0;i < layerExtensions.ExtensionCount;i++)
                {
                    if (layerExtensions.get_Extension(i) is I3DProperties)
                    {
                        p3DProperties = layerExtensions.get_Extension(i) as I3DProperties;
                    }
                }
                p3DProperties.BaseOption = esriBaseOption.esriBaseSurface;
                p3DProperties.BaseSurface = surface;
                p3DProperties.Apply3DProperties(pRasterlayer);