Creating a Terrain
To create a terrain using the Landscape Tool perform the steps described in the chapters below.
1. Specifying Data Sources
Landscape tool creates the terrain based on the real geodata sources, hence you should specify the data sources before proceeding. All data sources are divided into five types (layers):
- Elevation (optional) - this type of data is used to generate terrain geometry.
- Imagery - this type of data is used to generate textures for the terrain surface.
- Landcover (optional) - this type of data is used to generate natural features of the landscape (details, grass, trees, etc.).
- Vector (optional) - this type of data is used to generate roads, communications, buildings, landmarks, etc.
- Procedural (optional) - this type of data is used for procedural refinement.
To add a new source, click the Add Source button. In the opened windows specify the following fields:
|Layer||The imagery, elevation, landcover, vector or procedural layer of the data source.|
|Name||The name of the layer that will be displayed in the Data Sources panel.|
|Path||The path to the data source file or folder. Select the corresponding type of the data source Add Files or Add Folder.|
When you add the imagery, elevation, landcover, vector or procedural data sources to the Landscape tool, their areas will be highlighted on the Preview panel with corresponding colors: blue for elevation, green for imagery, red for landcover, yellow for vector and magenta for procedural. Area size of procedural sources is adjustable.
The minus sign button deletes selected data source.
2. Specifying Data Source Parameters
When you select a data source, you can see its parameters in the Parameters panel.
Elevation data source parameters are as shown below.
You can specify the following parameter:
|Elevation scale||The scale factor used for elevation data.|
Imagery data source parameters are as shown below.
You can specify the following parameter:
|No data color||The color to be used for areas with no data available.|
Landcover data source parameters are described here. This type of data source is optional and should be added when generation of terrain details or vegetation is needed.
Vector data source parameters are described here. This type of data source is optional and should be added when generation of roads, communications, buildings, landmarks, etc. is needed.
Procedural data source parameters are described here. This type of data source is optional and should be added when it is necessary to refine data from elevation, landcover or other procedural data sources.
3. Setting Up Natural Layer
At this step you can check out the parameters of Terrain LODs to be generated for all data layers (elevation, imagery, normal, and detail masks) and determine the natural features of the landscape.
To access LOD settings for your terrain you should select the Terrain LODs item in the list, all available settings will be displayed on the Parameters panel.
The Landscape Tool sets the number of LODs, their visibility distances and densities automatically. You can change these settings when necessary. To modify LOD settings for the desired data layer you should set Manual mode by checking the corresponding option located just under the list of LODs (see the picture below).
In the manual mode you can modify density and visibility distance values by simply double-clicking on the corresponding cell and entering the desired value.
Here you can also determine, which natural features of the landscape are to be generated:
Terrain detail masks - the tags specified for landcover data sources that determine the areas for terrain details to be placed.
Workflow: Generating Detail Masks.
Workflow: Generating Vegetation.
4. Setting Up Cultural Layer
At this step you can determine which cultural features of the landscape are to be generated: roads, communications, fences, pipes, buildings, landmarks, etc.
Objects of this layer are divided into 3 groups depending on the type of vector data used for their generation:
Spline (Roads, Communications, etc.) - objects of this type are stretched or tiled along Bezier splines.
Workflow: Generating Spline Objects.
Vector (Fences, Pipes, etc.) - objects of this type are generated and placed along vectors.
Workflow: Generating Vector Objects.
Point (Buildings, Landmarks, etc.) - objects of this type are generated and placed at certain points.
Workflow: Generating Point Objects.
5. Specifying Settings
Landscape tool generates a terrain according to the specified settings. Set the following parameters before starting terrain generation:
Here you can specify the output path for your terrain data and cache parameters. When the Landscape tool faces a large amount of source data, it automatically cuts the data to small tiles and uses them as cache. The cache is used to speed up subsequent terrain re-generation.
- Landscape tool doesn't clear the cache automatically, you should do it manually if necessary.
- When clearing the cache remember, that next terrain re-generation will require more time.
|Output path||Output path for generated terrain files. By default, a new folder in your project's data folder will be created.|
|Cache path||Path to cache files.|
|Max cache size (GB)||Maximum size of cache files on the hard drive (in GB)|
|Cache size on disk (GB)||Size of cache files on the hard drive (in Gb)|
|Clear cache||Click this button to delete all cache for the current landscape asset.|
Play Area is a rectangular area of a landscape to be generated.
Play Area represents a gray outlined rectangular area in the Preview panel. Due to the equirectangular projection, it looks like a trapezium near the terrestrial poles.
Click on the Play Area settings. In the Parameters panel the available parameters for Play Area will appear:
You can specify the following parameters:
|Center||The central point coordinates of the Play Area.|
|Size (km)||The size of the Play Area: width x height|
Here you can specify the order in which data sources will be processed. By default, data sources are processed in the order from the most detailed to the less detailed ones (e.g. a data source having the density of 3 meters/pixel will be processed before a data source having the density of 30 meters/pixel). But in some cases it might be necessary to change the order of processing for certain types of data sources. To do so, pefrorm the following actions:
- On the Parameters panel select a tab, corresponding to a group of data sources, for which the processing order is to be changed.
- For each item in the list of data sources displayed click a cell in the Order column and set the desired processing priority value.A data source having the priority value of 2 will be processed before the one that has the priority value of 3.
- After setting new processing priorities for data sources click Apply.
Let us consider an example of a case when you need to change default priority. Suppose You have the following data sources:
- A coarse 100 m/px elevation data source Elev1.
- A procedural data source Proc1 with the density of 10 m/px which refines the data from Elev1.
- A procedural data source Proc2 with the same density of 10 m/px which operates with the data refined by Proc1.
So, the expected data flow diagram would be: Elev1 -> Proc1 -> Proc2.
But generally, as both procedural data sources have the same density, default prioritization may result in the following data flow diagram: Elev1 -> Proc2 -> Proc1.
Which definitely is not the same. This situation can be avoided by setting the priority of the Proc1 source equal to 2 (as the default priority value for Houdini assets is 1).
Generating a Terrain
The Landscape Tool stores the paths to all data sources as well as all generation parameters in an asset. So, after setting up all these parameters, you should save them by choosing File -> Save Asset and specifying the name and path for your asset.
Now you can generate the terrain by clicking the Generate button.
In the Generation Steps window, that appears, you can select what is to be generated.
|Generate all||The whole terrain with detail masks, landcover objects and vector objects (spline, vector, and point) will be generated. This option is selected by default.|
|Terrain||Only terrain will be generated. Here you can select parts of terrain data used for generation (Elevation, Imagery, Details)|
|Landcover objects||Only landcover objects will be generated.|
|Vector objects||Only vector objects will be generated.|
|Curved||The flag indicating if the generated terrain should be curved (WGS-84 ellipsoid datum).
Landscape tool uses WGS-84 ellipsoid by default. After terrain generation, you can specify the Geodetic Pivot object's settings and choose another ellipsoid reference (including custom).
|Imagery previews||The flag indicating if imagery previews are to be generated and placed at the corresponding location on the map displayed on the Preview panel. Thus, you can mark areas of the global map for which the terrain was generated.|
If you have any unsaved changes, then after clicking OK in the Generation Steps window, you will see the window for saving the asset. Specify the name and the path for your asset and click Save.
The generation status window will appear.
After successful generation process, the Landscape tool may offer your world settings optimizations. We recommend you to apply them, however, you can ignore.
If you open the Nodes window, you can see that the Landscape tool created the following instances:
- The landscape_geodetic_pivot Geodetic Pivot object for curving the terrain according to WGS-84 ellipsoid.This object will be generated only when Curved option is selected in the Generation Steps window
- TerrainGlobal Landscape object.
- Beacons - NodeDummy objects generated for all elevation sources in the Play Area. These beacons can be used to quickly move to certain terrain location.
- The Landscape Camera camera object which is placed in the center point of the terrain with specified all the necessary parameters (far and near clipping planes).