Skip to content

Latest commit

 

History

History
100 lines (74 loc) · 3.42 KB

obi_particles.md

File metadata and controls

100 lines (74 loc) · 3.42 KB
Raw
Physics (Obi)

ObiParticles output data

Obi particle data

Obi makes a distinction between actors and non-actors. An actor has an array of particles which deform the geometry of the object.

In this minimal example, the honey fluid is an actor and has particle data; the rh10 model is a non-actor.

from tdw.controller import Controller
from tdw.tdw_utils import TDWUtils
from tdw.add_ons.obi import Obi
from tdw.add_ons.third_person_camera import ThirdPersonCamera
from tdw.obi_data.fluids.cube_emitter import CubeEmitter

c = Controller()
c.communicate(TDWUtils.create_empty_room(12, 12))
fluid_id = Controller.get_unique_id()
camera = ThirdPersonCamera(position={"x": 1.2, "y": 1.5, "z": -1.5},
                           look_at={"x": 0, "y": 0, "z": 0})
obi = Obi()
c.add_ons.extend([camera, obi])
obi.create_fluid(fluid="honey",
                 shape=CubeEmitter(),
                 object_id=fluid_id,
                 position={"x": 0, "y": 2.35, "z": 0},
                 rotation={"x": 90, "y": 0, "z": 0},
                 speed=1)
c.communicate(Controller.get_add_physics_object(model_name="rh10",
                                                object_id=Controller.get_unique_id()))
for i in range(80):
    c.communicate([])
c.communicate({"$type": "terminate"})

In TDW, each actor's particle can be sent to the controller. The Obi add-on automatically sends send_obi_particles and receives ObiParticles output data.

Compared to other output data in TDW, ObiParticles is difficult to use as-is. In Obi, the organization of the particle data prioritizes speed over ease of use, and that decision is reflected in TDW as well. The Obi add-on include a dictionary: obi.actors. The key of this dictionary is the ID of an actor and the value is an ObiActor, a data class that is better-organized.

This example controller adds a fluid to the scene and prints the positions and velocities of its particles per frame:

from tdw.controller import Controller
from tdw.tdw_utils import TDWUtils
from tdw.add_ons.obi import Obi
from tdw.obi_data.fluids.cube_emitter import CubeEmitter

c = Controller()
c.communicate(TDWUtils.create_empty_room(12, 12))
fluid_id = Controller.get_unique_id()
obi = Obi()
c.add_ons.append(obi)
obi.create_fluid(fluid="honey",
                 shape=CubeEmitter(),
                 object_id=fluid_id,
                 position={"x": 0, "y": 2.35, "z": 0},
                 rotation={"x": 90, "y": 0, "z": 0},
                 speed=1)
c.communicate([])
for i in range(10):
    c.communicate([])
    for actor_id in obi.actors:
        print(obi.actors[actor_id].positions)
        print(obi.actors[actor_id].velocities)
c.communicate({"$type": "terminate"})

Disable particle data

To disable particle data, set output_data=False in the Obi constructor:

from tdw.add_ons.obi import Obi

obi = Obi(output_data=False)

Next: Colliders and collision materials

Return to the README

Python API:

Command API:

Output data: