Scene Objects

A scene is made of scene objects. Examples include cars, trees,buildings, furniture, etc.A scene object is characterized by its geometry and material (RadioMaterial)and implemented as an instance of theSceneObject class.

Scene objects are uniquely identified by their name.To access a scene object, theget() method ofScene may be used.For example, the following code snippet shows how to load a scene and list its scene objects:

scene=load_scene(sionna.rt.scene.munich)print(scene.objects)

To select an object, e.g., named“Schrannenhalle-itu_metal”, you can run:

my_object=scene.get("Schrannenhalle-itu_metal")

You can then set theRadioMaterialofmy_object as follows:

my_object.radio_material="itu_wood"

classsionna.rt.SceneObject(mi_mesh=None,name=None,fname=None,radio_material=None,remove_duplicate_vertices=False)[source]

Class implementing a scene object

Scene objects can be either created from an existing Mitsuba shapeor by loading a mesh from a file. In the latter case, a nameand radio material for the scene object must be provided.

To create a scene object from a mesh file, use the following approach:

obj=SceneObject(fname=sionna.rt.scene.sphere,name="sphere",radio_material=ITURadioMaterial(name="sphere-material",itu_type="metal",thickness=0.01))

To instantiate a scene object using a Mitsuba shape, follow these steps:

mesh=load_mesh(sionna.rt.scene.sphere)obj=SceneObject(mi_mesh=mesh,name="sphere",radio_material=ITURadioMaterial(name="sphere-material",itu_type="metal",thickness=0.01))

Parameters:

• mi_mesh (typing.Optional[mitsuba.Mesh]) – Mitsuba shape.Must be provided iffname isNone.

• name (typing.Optional[str]) – Object name.Must be provided iffname is notNone.

• fname (typing.Optional[str]) – Filename of a valid mesh ( “.ply” | “.obj”).Must be provided ifmi_mesh isNone.

• radio_material (typing.Optional[sionna.rt.radio_materials.radio_material_base.RadioMaterialBase]) – Radio material of the object.Must be provided iffname is notNone.

• remove_duplicate_vertices (bool)

clone(name=None,as_mesh=False,props=None)[source]

Creates a clone of the current scene object

The clone will have the same geometry and material properties as theoriginal object but will be assigned a new name.

Parameters:

• name (typing.Optional[str]) – Name (id) of the cloned object.IfNone, the clone will be named as<original_name>-clone.

• as_mesh – If set toTrue, the clone will be returned as amitsuba.Mesh object. Otherwise, asionna.rt.SceneObject will be returned.

• props (typing.Optional[mitsuba.Properties]) – Pre-populated properties to be used in the new Mitsubashape. Allows overriding the BSDF, emitter, etc.

Return type:

sionna.rt.scene_object.SceneObject |mitsuba.Mesh

Returns:

A clone of the current object

look_at(target)[source]

Sets the orientation so that the x-axis points toward a position

Parameters:

target (mitsuba.Point3f |sionna.rt.radio_devices.radio_device.RadioDevice |str) – A position or the name or instance of anobject in the scene to point toward to

propertymi_mesh

Get/set the Mitsuba shape

Type:

mi.Mesh

propertyname

Name

Type:

str

propertyobject_id

Identifier

Type:

int

propertyorientation

Get/set the orientation [rad] specified through three angles\((\alpha, \beta, \gamma)\) corresponding to a 3D rotation asdefined in(3)

Type:

mi.Point3f

propertyposition

Get/set the position vector [m] of the center of the object. Thecenter is defined as the object’s axis-aligned bounding box (AABB).

Type:

mi.Point3f

propertyradio_material

Get/set the radio material of the object. Setting can be done byusing either an instance ofRadioMaterialBase orthe material name (str).

Type:

RadioMaterialBase

propertyscaling

Get the scaling in the coordinate system of the object.If a scalar value is provided, the object is uniformly scaledacross all dimensions by that value. Alternatively, if a vectoris provided, the object is scaled independently along the x, y,and z axes according to the respective components of the vector,within the object’s coordinate system.

Type:

mi.Float |mi.Vector3f

propertyscene

Get/set the scene to which the object belongs. Note that the scene canonly be set once.

Type:

sionna.rt.Scene

propertyvelocity

Get/set the velocity vector [m/s]

The velocity must to be set at least once before it can bedifferentiated.

Type:

mi.Vector3f