public IMultiPatch CreateMultipatch()
...{
    //Prepare the geometry material list.
    IGeometryMaterial texture = new GeometryMaterialClass();
    texture.TextureImage = "C:\\Temp\\MyImage.bmp";

    IGeometryMaterialList materialList = new GeometryMaterialListClass();
    materialList.AddMaterial(texture);

    //Create the multipatch.
    IGeneralMultiPatchCreator multiPatchCreator = new GeneralMultiPatchCreatorClass();
    multiPatchCreator.Init(4, 1, false, false, false, 4, materialList);

    //Set up part.

    //Could also use a Ring or a TriangleFan.
    multiPatchCreator.SetPatchType(0, esriPatchType.esriPatchTypeTriangleStrip);
    multiPatchCreator.SetMaterialIndex(0, 0);
    multiPatchCreator.SetPatchPointIndex(0, 0);
    multiPatchCreator.SetPatchTexturePointIndex(0, 0);

    //Set real-world points.
    WKSPointZ upperLeft  = new WKSPointZ();
    WKSPointZ lowerLeft  = new WKSPointZ();
    WKSPointZ upperRight = new WKSPointZ();
    WKSPointZ lowerRight = new WKSPointZ();

    upperLeft.X = 0;
    upperLeft.Y = 0;
    upperLeft.Z = 0;
    upperRight.X = 300;
    upperRight.Y = 0;
    upperRight.Z = 0;
    lowerLeft.X = 0;
    lowerLeft.Y = 0;
    lowerLeft.Z = -100;
    lowerRight.X = 300;
    lowerRight.Y = 1;
    lowerRight.Z = -100;

    multiPatchCreator.SetWKSPointZ(0, ref upperRight);
    multiPatchCreator.SetWKSPointZ(1, ref lowerRight);
    multiPatchCreator.SetWKSPointZ(2, ref upperLeft);
    multiPatchCreator.SetWKSPointZ(3, ref lowerLeft);

    //Set texture points.
    //Set the texture coordinates for a panel.
    WKSPoint textureUpperLeft  = new WKSPoint();
    WKSPoint textureLowerLeft  = new WKSPoint();
    WKSPoint textureUpperRight = new WKSPoint();
    WKSPoint textureLowerRight = new WKSPoint();

    textureUpperLeft.X = 0;
    textureUpperLeft.Y = 0;
    textureUpperRight.X = 1;
    textureUpperRight.Y = 0;
    textureLowerLeft.X = 0;
    textureLowerLeft.Y = 1;
    textureLowerRight.X = 1;
    textureLowerRight.Y = 1;

    multiPatchCreator.SetTextureWKSPoint(0, ref textureUpperRight);
    multiPatchCreator.SetTextureWKSPoint(1, ref textureLowerRight);
    multiPatchCreator.SetTextureWKSPoint(2, ref textureUpperLeft);
    multiPatchCreator.SetTextureWKSPoint(3, ref textureLowerLeft);
    IMultiPatch multiPatch = multiPatchCreator.CreateMultiPatch() as IMultiPatch;

    return multiPatch;
}

 参考资料：ArcEngine 9.2帮助文档