Working with 3D Mesh Layers 

Mesh layers are multi-resolution, textured mesh models that may include classification layers, as well as polygons from BIM datasets. They are created through automatic reconstruction methods, manual modeling, or building information modeling (BIM). Mesh layers can be loaded into TerraExplorer from files or from SkylineGlobe or 3D Tile servers, and displayed on the terrain, as well as measured and analyzed. Mesh layers can be classified using polygons (generally from a feature layer) that enable you to visually distinguish different areas of the mesh layer, access the attribute data of the classification features and perform spatial and attribute queries. The classification is dynamic, reflecting any changes to the polygon features, and requires no pre-processing.

Mesh layers created from point feature layers with individually referenced 3D model files, imported BIM layers, and mesh layers classified using the legacy Classify Mesh Layer tools include associated feature layers that are pre-processed with their respective mesh layers. These mesh layers support many of the editing, analysis, and querying capabilities available for standard feature layers, e.g., spatial and attribute queries.

The following mesh layers are supported in TerraExplorer. Most mesh layers are converted to Skyline’s proprietary, stream-optimized 3DML format, upon import.

§  Mesh models – Automatically generated from standard 2D photographs in PhotoMesh.

§  Mesh + Classification – Mesh layers classified in older versions of TerraExplorer, by associating and pre-processing polygon feature layers with the mesh (legacy support).

Note:        TerraExplorer's new mesh classification method is dynamic and does not pre-process the classification layers with any particular mesh. See "Classifying Layers and Objects Using Feature Layers" in the "Feature Layers" chapter for information.

§  Models (Point feature layers that reference individual models) – Model layers are converted to 3DML in TerraExplorer using the Models to 3DML tool.

§  DAE (LODTreeExport.xml) – DAE (LODTreeExport.xml) layers are converted to 3DML upon import to TerraExplorer using the Import and Convert tools.

§  OSGB – OSGB layers are converted to 3DML upon import to TerraExplorer using the Import and Convert tools.

§  3D Tiles (tileset.json) – 3D Tiles layers are converted to 3DML upon import to TerraExplorer using the Import and Convert tools.

§  Building Information Modeling (BIM) – BIM layers are converted to 3DML upon import to TerraExplorer using the Import BIM tool.

§  Mesh + Classification + Models – These are merged in the legacy CityBuilder application into a 3DML.

When a mesh layer is loaded into TerraExplorer, the 3D Mesh Layer contextual tab is displayed, from which you can perform mesh layer operations. Most of the mesh layer operations are available only for mesh layers in 3DML format.

The following mesh layer operations are supported:

§  Set Display Style – Select a mesh model display style, e.g., texture, wireframe, or x-ray.

§  Classify – Create a feature layer with classification polygons containing attribute data relevant to the mesh layer. Classification enables you to visually distinguish different areas of the mesh layer and perform spatial and attribute queries on the feature layer that is classifying the mesh layer. 

§  Modify – Modify the elevation values in a designated area of a 3DML using a modify mesh layer object.

§  Mark for Retouch – Edit mesh imperfections, such as bumps, irregular surfaces, or floating artifacts.

§  Scale and Rotate – Correct inaccuracies in mesh layers’ scale, rotation and positioning.

§  Export to Models – Export polygonal areas of a 3DML, e.g., buildings, to individual OBJ models.

§  Export to Mesh – Export 3DML to 3D Tiles (tileset.json) or I3S/SLPK formats.

Some operations are only available for mesh layers with associated feature layers (i.e., mesh created from point feature layers with individually referenced 3D model files, imported BIM layers, or mesh layers classified using the legacy Classify Mesh Layer tools):

§  Spatial Queries - Select features based on their spatial relationship with a polygon, line or point that you draw, or with an existing object.

§  Search by Attribute - Search the layer attribute database files to easily edit the attribute values of multiple features and to create a new shapefile based on the filtered data. 

§  Display by Attribute - Display only selected areas of the mesh model that match a specific attribute value.

§  Colorize by Attribute - Colorize the mesh model based on attribute value, with a different color assigned to each attribute value.

See “Working with 3DML’s Feature Layers” in this chapter for more information.