Configuring the Spatial Awareness Mesh Observer
For every Spatial Mesh Observer entry in the Spatial Awareness System profile, the Mesh Observer Profile must define the type implementation and the list of supported platform(s) to run this observer.
The default implementation type for IMixedRealitySpatialAwarenessMeshObserver provided by the Mixed Reality Toolkit is the WindowsMixedRealitySpatialMeshObserver.
The spatial awareness mesh observer profile also provides options for configuring:
General Settings
Startup Behavior
The startup behavior specifies the behavior of the observer when it is first instantiated. The options are Auto Start and Manual Start. The default value is Auto Start. When set to Manual Start, applications will need to call one of the following IMixedRealitySpatialAwarenessSystem methods:
- ResumeObserver<T>(string name)
- ResumeObservers()
- ResumeObservers<T>()
Update Interval
The time, in seconds, between requests to the platform to update spatial mesh data. Typical values fall in the range of 0.1 and 5.0 seconds.
Is Stationary Observer
Indicates whether or not the observer is to remain stationary or to move and update with the user.
When stationary, if the user moves further than the Observation Extents away from the origin, there will be no mesh data calculated until the users moves closer back to the origin.
Observer Shape
The observer shape defines the type of volume that the mesh observer will use when observing meshes. The supported options are:
Axis Aligned Cube
An axis aligned cube volume is a rectangular shape that stays aligned with the axes of the world coordinate system, as determined at application startup.
User Aligned Cube
A user aligned cube volume is a rectangular shape that rotates to align with the users local coordinate system.
Sphere
A spherical volume with a center at the world space origin. The X value of the Observation Extents property will be used as the radius of the sphere.
Observation Extents
The observation extents define the distance from the observation point that meshes will be observed.
Physics Settings
Physics Layer
The physics layer specifies which layer on which the spatial mesh objects will be placed in order to interact with the Unity Physics and RayCast systems. The Mixed Reality Toolkit reserves layer 31 by default for use by Spatial Awareness observers.
Recalculate Normals
Specifies whether or not the mesh observer will recalculate the normals of the mesh following observation. This setting is available to ensure applications receive meshes that contain valid normals data on platforms that do not return them with meshes.
Level of Detail Settings
Level of Detail
Specifies the level of detail (LOD) of the spatial mesh data. Currently defined values are Coarse, Fine and Custom.
The Coarse LOD generally places a smaller impact on application performance and are an excellent choice for navigation and plane finding.
The Fine LOD generally exacts a higher performance impact on application performance and are a great option for occlusion meshes.
The Custom LOD requires the application to specify the Triangles / Cubic Meter value and allows applications to tune the accuracy vs. performance impact of the spatial mesh observer.
Note
It is not guaranteed that all Triangles/Cubic Meter values are honored by all platforms. Experimentation and profiling is highly recommended when using a custom LOD.
Triangles per Cubic Meter
When using the custom Level of Detail, specifies the requested value for the triangle density for the spatial mesh.
Display Settings
Display Option
Specifies how spatial meshes are to be displayed by the observer. Supported values are None, Visible and Occlusion. Setting Visible or Occlusion instructs the observer to select the appropriate material. Specifying None causes the observer to not render the mesh.
Warning
Setting Display Option to None does not stop the observer from running. If you wish to stop the observer, applications will need to call one of the following IMixedRealitySpatialAwarenessSystem methods:
- SuspendObserver<T>(string name)
- SuspendObservers()
- SuspendObservers<T>()
Visible Material
Indicates the material to be used when visualizing the spatial mesh.
Occlusion Material
Indicates the material to be used to cause the spatial mesh to occlude holograms.