Address Contact Issues

[hang-yin]

Motivation

1. Small/light objects may fall asleep during motion after teleporting
2. RigidContactAPI does not give valid impulse/contact data even when two objects are clearly touching and awake

Fix

1. Lower sleep threshold from 0.001 to 0.00005
2. Lower contact threshold to 0.0; Use contact sensor instead for transition rules TouchingAnyCondition

Implications

1. We have three ways of checking contact in OG:

• RigidContactAPI:
  • This works when contacting objects are both awake, but not when they are asleep
  • We will use this when objects are guaranteed to be awake when we do the contact check
    • Assisted Grasping: robot fingers need to be moving and touching the object
    • ToggleOn: robot fingers need to be moving and touching the toggle button
    • SlicerActive: slicer need to be moving and touching the sliceable
• Simulator _on_contact callback:
  • This triggers whenever there's contact; currently only used for attachment
• Contact sensor:
  • This works regardless if an object is awake or asleep, presumably because of some internal contact caching mechanism
  • We will use this when motion/objects being awake is not guaranteed:
    • Transition Rules TouchingAnyCondition
    • ContactBodies
    • Touching

2. In general, contact sensor query is slower than batched RigidContactAPI query. Going forward, we will try to use RigidContactAPI whenever possible, and use contact sensor as a fallback.

[cremebrule]

just a few comments! thanks for looking into this!!

btw, forcing objects awake doesn't make RigidContactAPI work? And if so, why is that?????

[hang-yin]

comments! thanks for looking into this!!

btw, forcing objects awake doesn't make RigidContactAPI

I guess the point is that if objects need explicit waking before generic contact checking, this check would generally be slow. We could potentially benchmark contact sensor call against waking+RigidContactAPI

[cgokmen]

LGTM, but are we undoing the transition rule thing?