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 the SceneObject class.

Scene objects are uniquely identified by their name. To access a scene object, the get() method of Scene 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 the RadioMaterial of my_object as follows:

my_object.radio_material = "itu_wood"

Most scene objects names have postfixes of the form “-material_name”. These are used during loading of a scene to assign a RadioMaterial to each of them. This tutorial video explains how you can assign radio materials to objects when you create your own scenes.

class sionna.rt.SceneObject(mi_shape=None, name=None, fname=None, radio_material=None)

Class implementing a scene object

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

Parameters:

• mi_shape (typing.Optional[mitsuba.Mesh]) – Mitsuba shape. Must be provided if fname is None.

• name (typing.Optional[str]) – Object name. Must be provided if fname is not None.

• fname (typing.Optional[str]) – Filename of a valid mesh ( “.ply” | “.obj”). Must be provided if mi_shape is None.

• radio_material (typing.Optional[sionna.rt.radio_materials.radio_material_base.RadioMaterialBase]) – Radio material of the object. Must be provided if fname is not None.

look_at(target)

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

Parameters:

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

property mi_shape

Get/set the Mitsuba shape

Type:

mi.Mesh

property name

Name

Type:

str

property object_id

Identifier

Type:

int

property orientation

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

Type:

mi.Point3f

property position

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

Type:

mi.Point3f

property radio_material

Get/set the radio material of the object. Setting can be done by using either an instance of RadioMaterialBase or the material name (str).

Type:

RadioMaterialBase

property scaling

Get/set the scaling

Type:

mi.Float

property scene

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

Type:

sionna.rt.Scene

property velocity

Get/set the velocity vector [m/s]

Type:

mi.Vector3f