As mentioned earlier, TDW doesn't impose metaphors regarding what an agent is or whether there needs to be one at all. Avatars are a type of agent in TDW but not the only one.
All avatars have a camera. The most commonly used avatar is a non-embodied camera or "third-person camera". There is a more streamline API for third-person cameras, which will be covered in the next document.
To add the third-person camera avatar to the scene:
from tdw.controller import Controller
from tdw.tdw_utils import TDWUtils
c = Controller()
c.communicate([TDWUtils.create_empty_room(12, 12),
{"$type": "create_avatar",
"type": "A_Img_Caps_Kinematic",
"id": "a"}])...which will render this image in the build application's window:
The avatar is currently at position (0, 0, 0) i.e. floor level--the top half of the image is above the floor and the bottom half is below the floor. To move the avatar to a better location, send teleport_avatar_to:
from tdw.controller import Controller
from tdw.tdw_utils import TDWUtils
c = Controller()
c.communicate([TDWUtils.create_empty_room(12, 12),
{"$type": "create_avatar",
"type": "A_Img_Caps_Kinematic",
"id": "a"},
{"$type": "teleport_avatar_to",
"avatar_id": "a",
"position": {"x": -1, "y": 0.6, "z": 2.4}}])...which will render this image:
This is a little better (the camera is now above floor level) but still not great. Let's rotate the avatar's sensor container (its camera) for a better view of the scene:
from tdw.controller import Controller
from tdw.tdw_utils import TDWUtils
c = Controller()
c.communicate([TDWUtils.create_empty_room(12, 12),
{"$type": "create_avatar",
"type": "A_Img_Caps_Kinematic",
"id": "a"},
{"$type": "teleport_avatar_to",
"avatar_id": "a",
"position": {"x": -1, "y": 5.7, "z": -3.8}},
{"$type": "rotate_sensor_container_by",
"axis": "pitch",
"angle": 26,
"avatar_id": "a"},
{"$type": "rotate_sensor_container_by",
"axis": "yaw",
"angle": -15,
"avatar_id": "a"}])...which will render this image:
TDWUtils includes a helpful wrapper function for creating avatars: create_avatar():
from tdw.controller import Controller
from tdw.tdw_utils import TDWUtils
c = Controller()
commands = [TDWUtils.create_empty_room(12, 12)]
commands.extend(TDWUtils.create_avatar(avatar_type="A_Img_Caps_Kinematic",
position={"x": -1, "y": 5.7, "z": -3.8},
look_at={"x": 0, "y": 1, "z": 0}))
c.communicate(commands)...which will render this image:
To move and rotate the avatar, simply teleport and rotate it by small increments per frame:
from tdw.controller import Controller
from tdw.tdw_utils import TDWUtils
"""
Move the avatar and rotate the camera.
Note that in this example, the `avatar_id` parameters are missing. That's because they all default to "a".
"""
c = Controller()
y = 5.7
c.communicate([TDWUtils.create_empty_room(12, 12),
{"$type": "create_avatar",
"type": "A_Img_Caps_Kinematic",
"id": "a"},
{"$type": "teleport_avatar_to",
"position": {"x": -1, "y": y, "z": -3.8}},
{"$type": "rotate_sensor_container_by",
"axis": "pitch",
"angle": 26},
{"$type": "set_target_framerate",
"framerate": 30}])
for i in range(20):
y += 0.1
c.communicate([{"$type": "rotate_sensor_container_by",
"axis": "yaw",
"angle": 2},
{"$type": "teleport_avatar_to",
"position": {"x": -1, "y": y, "z": -3.8}}])
c.communicate({"$type": "terminate"})...which moves the avatar like this:
There are several embodied avatars in TDW which can be useful for prototyping. Read this for more information.
Next: Add-ons and the ThirdPersonCamera
Example controllers:
- move_avatar.py Move an avatar and rotate its camera.
Python API:
Command API: