obi.md

Obi

from tdw.add_ons.obi import Obi

This add-on handles most aspects of an Obi physics simulation, including initialization, actor creation, and particle output data.

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Fields

• actors A dictionary of Obi actor data. Key = Object ID. Value = ObiActor. The particle data is updated if output_data == True (see above).

• wind_sources A dictionary of wind sources. Key = Wind source ID. Value = WindSource. To add a wind source, add a new WindSource to this dictionary; it will be automatically created and updated. See the WindSource API for how to dynamically set wind parameters.

• commands These commands will be appended to the commands of the next communicate() call.

• initialized If True, this module has been initialized.

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Functions

__init__

Obi()

Obi(output_data=True, floor_material=None, object_materials=None, vr_material=None, exclude=None, backend=ObiBackend.burst)

Parameter	Type	Default	Description
output_data	bool	True	If True, receive ObiParticles per frame.
floor_material	CollisionMaterial	None	The floor's CollisionMaterial. If None, uses default values.
object_materials	Dict[int, CollisionMaterial]	None	Overrides for object and robot collision materials. Key = Object or Robot ID. Value = CollisionMaterial.
vr_material	CollisionMaterial	None	If there is a VR rig in the scene, its hands will have this CollisionMaterial. If None, uses default values.
exclude	List[int]	None	Exclude these objects from receiving Obi collision materials.
backend	ObiBackend	ObiBackend.burst	The ObiBackend for each solver.

get_initialization_commands

self.get_initialization_commands()

This function gets called exactly once per add-on. To re-initialize, set self.initialized = False.

Returns: A list of commands that will initialize this add-on.

on_send

self.on_send(resp)

This is called within Controller.communicate(commands) after commands are sent to the build and a response is received.

Use this function to send commands to the build on the next Controller.communicate(commands) call, given the resp response. Any commands in the self.commands list will be sent on the next Controller.communicate(commands) call.

Parameter	Type	Default	Description
resp	List[bytes]		The response from the build.

before_send

self.before_send(commands)

This is called within Controller.communicate(commands) before sending commands to the build. By default, this function doesn't do anything.

Parameter	Type	Default	Description
commands	List[dict]		The commands that are about to be sent to the build.

get_early_initialization_commands

self.get_early_initialization_commands()

This function gets called exactly once per add-on. To re-initialize, set self.initialized = False.

These commands are added to the list being sent on communicate() before any other commands, including those added by the user and by other add-ons.

Usually, you shouldn't override this function. It is useful for a small number of add-ons, such as loading screens, which should initialize before anything else.

Returns: A list of commands that will initialize this add-on.

create_fluid

self.create_fluid(object_id, fluid, shape)

self.create_fluid(object_id, fluid, shape, position=None, rotation=None, speed=0, lifespan=4, minimum_pool_size=0.5, solver_id=0)

Create a cube-shaped fluid emitter.

Parameter	Type	Default	Description
object_id	int		The unique ID of the emitter.
fluid	Union[str, Fluid, GranularFluid]		Either a Fluid, a GranularFluid, the name of a fluid (see Fluid.FLUIDS), or the name of a granular fluid (see GranularFluid.GRANULAR_FLUIDS).
shape	EmitterShape		Either a CubeEmitter, DiskEmitter, EdgeEmitter, or SphereEmitter.
position	Dict[str, float]	None	The position of the emitter object. If None, defaults to {"x": 0, "y": 0, "z": 0}.
rotation	Dict[str, float]	None	The rotation of the emitter object, in Euler angles. If None, defaults to {"x": 0, "y": 0, "z": 0}.
speed	float	0	The speed of emission in meters per second. If 0, there is no emission.
lifespan	float	4	The particle lifespan in seconds.
minimum_pool_size	float	0.5	The minimum amount of inactive particles available before the emitter is allowed to resume emission.
solver_id	int	0	The ID of the Obi solver.

create_cloth_sheet

self.create_cloth_sheet(object_id, cloth_material)

self.create_cloth_sheet(object_id, cloth_material, sheet_type=SheetType.cloth_hd, position=None, rotation=None, solver_id=0, tether_positions=None)

Create a cloth sheet.

Parameter	Type	Default	Description
object_id	int		The unique ID of the cloth sheet.
cloth_material	Union[str, ClothMaterial]		Either a ClothMaterial or the name of a cloth material (see Cloth.CLOTH_MATERIALS)).
sheet_type	SheetType	SheetType.cloth_hd	The SheetType.
position	Dict[str, float]	None	The position of the cloth sheet. If None, defaults to {"x": 0, "y": 0, "z": 0}.
rotation	Dict[str, float]	None	The rotation of the cloth sheet, in Euler angles. If None, defaults to {"x": 0, "y": 0, "z": 0}.
solver_id	int	0	The ID of the Obi solver.
tether_positions	Dict[TetherParticleGroup, TetherType]	None	An dictionary of tether positions. Key = TetherParticleGroup. Value = TetherType. Can be None.

create_cloth_volume

self.create_cloth_volume(object_id, cloth_material, volume_type)

self.create_cloth_volume(object_id, cloth_material, position=None, rotation=None, scale_factor=None, pressure=0.5, volume_type, solver_id=0)

Create a cloth volume.

Parameter	Type	Default	Description
object_id	int		The unique ID of the cloth sheet.
cloth_material	Union[str, ClothMaterial]		Either a ClothMaterial or the name of a cloth material (see Cloth.CLOTH_MATERIALS)).
position	Dict[str, float]	None	The position of the cloth volume. If None, defaults to {"x": 0, "y": 0, "z": 0}.
rotation	Dict[str, float]	None	The rotation of the cloth volume, in Euler angles. If None, defaults to {"x": 0, "y": 0, "z": 0}.
scale_factor	Dict[str, float]	None	The scale factor of the mesh. If None, defaults to {"x": 1, "y": 1, "z": 1}.
pressure	float	0.5	The inflation amount of this cloth volume.
volume_type	ClothVolumeType		The VolumeType.
solver_id	int	0	The ID of the Obi solver.

set_fluid_speed

self.set_fluid_speed(object_id, speed)

Set the speed of a fluid emitter. By default, the speed of an emitter is 0 (no fluid emission).

Parameter	Type	Default	Description
object_id	int		The ID of the fluid emitter.
speed	float		The speed in meters per second. Set this to 0 to stop emission.

apply_force_to_cloth

self.apply_force_to_cloth(object_id)

self.apply_force_to_cloth(object_id, force=None, torque=None, force_mode=ForceMode.impulse)

Apply a uniform force and/or torque to a cloth actor.

Parameter	Type	Default	Description
object_id	int		The ID of the cloth actor.
force	Dict[str, float]	None	The force. If None, defaults to {"x": 0, "y": 0, "z": 0}.
torque	Dict[str, float]	None	The torque. If None, defaults to {"x": 0, "y": 0, "z": 0}.
force_mode	ForceMode	ForceMode.impulse	The ForceMode for the force and/or torque.

untether_cloth_sheet

self.untether_cloth_sheet(object_id, tether_position)

Untether a cloth sheet.

Parameter	Type	Default	Description
object_id	int		The ID of the cloth sheet.
tether_position	TetherParticleGroup		The TetherParticleGroup describing the position.

set_solver

self.set_solver()

self.set_solver(solver_id=0, substeps=1, scale_factor=1)

Set the parameters of a solver.

Parameter	Type	Default	Description
solver_id	int	0	The solver ID.
substeps	int	1	The number of substeps. More substeps can increase accuracy at the cost of performance.
scale_factor	float	1	The scale of the solver. This will uniformly scale all objects assigned to the solver.

reset

self.reset()

self.reset(floor_material=None, object_materials=None, vr_material=None)

Parameter	Type	Default	Description
floor_material	CollisionMaterial	None	The floor's CollisionMaterial. If None, uses default values.
object_materials	Dict[int, CollisionMaterial]	None	Overrides for object and robot collision materials. Key = Object or Robot ID. Value = CollisionMaterial.
vr_material	CollisionMaterial	None	If there is a VR rig in the scene, its hands will have this CollisionMaterial. If None, uses default values.