A Replicant is a human-like agent.
Replicants move via a combination of inverse kinematics (IK) for actions such as reaching for an object; the combined joint movement is fluid and plausible. Replicants can also perform arbitrary pre-recorded animations, meaning that specific complex actions are far easier to achieve than in a robotics simulation.
Replicants are visually similar to non-physics humanoids but do exist in a physics context. Replicants can cause physics events but won't respond to physics events. For example, if a Replicant walks into an object, it will push the object aside. Non-physics humanoids, on the other hand, will move through objects without interacting with them.
Replicants differ from robots in that they aren't entirely physics-driven. In addition to being massless, Replicant joints aren't defined as motorized drives. Joint velocity, momentum, etc. aren't concepts that exist in the context of a Replicant.
Replicants are thus a compromise on realism: It is far easier to achieve complex behavior with a Replicant than with a robot. On the other hand, the Replicant's motion itself isn't driven by physics to the extent that a robot's would be.
Like robots, Replicants are agents but are not avatars in TDW. Avatar commands won't work with robots.
Like robots, Replicants are best controlled via the Replicant add-on. Like all other add-ons, the Replicant add-on decomposes into low-level TDW commands but, given the complexity of the agent, we recommend that you always use the Replicant add-on rather than directly manipulating the agent with low-level commands.
Adding a Replicant to a scene is simple:
from tdw.controller import Controller
from tdw.tdw_utils import TDWUtils
from tdw.add_ons.replicant import Replicant
c = Controller()
replicant = Replicant()
c.add_ons.append(replicant)
c.communicate(TDWUtils.create_empty_room(12, 12))You can set the initial position and rotation of the Replicant in the constructor:
from tdw.controller import Controller
from tdw.tdw_utils import TDWUtils
from tdw.add_ons.replicant import Replicant
c = Controller()
replicant = Replicant(position={"x": 1, "y": 0, "z": -2},
rotation={"x": 0, "y": 30, "z": 0})
c.add_ons.append(replicant)
c.communicate(TDWUtils.create_empty_room(12, 12))There are additional constructor parameters that will be covered in subsequent documents.
Like objects and scenes, Replicants are asset bundles stored on a remote S3 server that must be downloaded before they can be added to the scene. This means that when you first add a Replicant to the scene, there will be a brief pause while it is downloaded and loaded into memory. For subsequent scene resets, the Replicant will already in memory and will appear immediately.
You can specify which Replicant asset bundle you want to use by setting the optional name parameter in the constructor. For example: replicant = Replicant(name="fireman").
The default Replicant is "replicant_0".
Like all other asset bundle types in TDW, Replicants have metadata records stored in the TDW Python module. Each Replicant has a corresponding HumanoidRecord, which is stored in a HumanoidLibrarian. To print the name of each available Replicant:
from tdw.librarian import HumanoidLibrarian
library = HumanoidLibrarian("replicants.json")
for record in library.records:
print(record.name)The Replicant is usable but unfinished. This version of the Replicant can be thought of as "Phase 1" and there are known limitations to it. These include:
- The Replicant's pose won't blend between animations, meaning that it will always snap back to a neutral pose at the start of an animation.
- The Replicant's turn action doesn't have an animation.
- The Replicant can't bend its fingers to achieve a realistic grasp action.
All of these limitations will be resolved in future phases of Replicant development. Additionally, more features will be added to the Replicant over time.
Next: Actions
Python API: