Terrain

The TerrainLocator is a locator node that determines the geometry of the ground on which to place crowd entities and to which the crowd entities will adapt, and the navigation mesh that will be used during the crowd simulation.

Creating a Terrain Locator can be performed through the following options:
  • Crowd Shelf: 
  • Crowd Menu: Terrain Locator
  • MEL command: glmTerrainLocatorCmd;
Notice that, computing a navigation mesh with the NavMesh Creator, automatically creates a Terrain Locator with the correct .gse file loaded. The input geometry used to generate the navMesh is also mapped to the Terrain Locator as ground geometry. If the Maya selection contains meshes when creating a Terrain Locator, they will also be mapped to the Terrain Locator.
 

Configuration

The parameters of the Terrain Locator are grouped into 5 main categories: Navigation Mesh Atributes, Ground Attributes, Display Attributes, Advanced Display Attributes and Locator Display Attributes.
 

Navigation Mesh Atributes

 
Attributes of a terrain locator
 
NavMesh File (.gse file) Navigation mesh to use in the crowd simulation and to display. The navigation mesh is required when using navigation and path finding (see GoTo Behavior and Navigation Behavior)

Ground Attributes

Ground Type this defines the ground to which the crowd entities will adapt during the crowd simulation. The available choices are:
  • Default Plane: the ground is considered to be an infinite plane at zero height (y = 0)
  • NavMesh Ground: the ground is the navMesh loaded from the NavMesh File attribute. This can be faster than Maya Geometry but also less accurate
  • Maya Geometry: this option allows to map any Maya geometry as ground to be used in the crowd simulation
In Maya Geometry shows which Maya nodes are mapped as ground geometry, when the Ground Type is set to Maya Geometry. Use the map and unmap buttons to change the mapped geometry (refer to the Usual Manipulations)
Dynamic Ground use this if the input geometry is animated. If checked, the ground geometry will be recomputed at each frame
Double Sided when checked, all the mapped geometry will be used as ground geometry, otherwise only the geometry facing up will be used

Display Attributes

Obstacle Borders (red lines)

when checked the locator displays the obstacles in the environment. If no NavMesh file is loaded nothing is displayed. When a terrain locator with a NavMesh is used with the Population Tool or with the GoTo Behavior and the Navigation Behavior, the zones surrounded by obstacle borders are not accessible by Entities
Roadmap (orange lines) graph linking all the accessible areas in the environment (edges between connected cells in the NavMesh are connected in the roadmap). If an area or a corridor is not covered by the roadmap, it means that it is not accessible.
Partial Borders (blue lines) these are special constraints in the navMesh. They can be crossed by crowd entities
Free Borders (grey lines) these are all the other edges in the navMesh that can be crossed by crowd entities
Navigation Cells (green lines and triangles) all the walkable cells of a navigation mesh
Ground Geometry (dark grey lines and triangles) the input ground geometry

Locator Display Attributes

 
Locator display attributes
 
Line Width the width of the lines drawn by the terrain locator
Locator Height the height difference to add to the lines drawn by the terrain locator
 
Notice that the same geometry with different the NavMesh Creator parameters can result in different navMeshes.
 
NavMesh generated with default parameters in Exact Subdivision Mode
 
The same navmesh generated with an 80° maximum navigation slope (notice inside the red circles some obstacles are gone)