Seeking advice on improving grasp stability and physics realism using mocap control

[Physics-Based Hand Grasping] Seeking advice on real-time object manipulation

Hi everyone,

I’m working on implementing a physics-based hand grasping system in UE5 driven by real-time motion capture input. I’m looking for feedback on achieving stable and realistic object manipulation.

Project Goal

Creating a system that allows characters to naturally interact with objects based on motion capture input, with a focus on realistic physics behavior during grabbing and manipulation.

Current Approach

The system uses:

  • Sphere colliders on hand bones for contact detection
  • OnHit events for contact registration
  • Contact point analysis for grasp evaluation
  • Physics constraints for object manipulation

Key Components:

  1. Contact System:

    • Sphere colliders attached to hand bones
    • Contact tracking with expiration threshold
    • Contact point analysis between fingers and objects
  2. Grasp Analysis:

    • Evaluates contact distribution
    • Considers thumb/palm involvement
    • Analyzes contact point patterns
  3. Physics Interaction:

    • Physics constraint creation/management
    • Multi-finger grasp handling
    • State-based interaction flow

Current Challenges

  1. Stability Issues:

    • Objects can slip during movement
    • Incorrect object positioning
    • Difficulty maintaining consistent grasp stability
  2. Physics Behavior:

    • Object jittering
    • Unnatural force distribution
    • Abrupt state transitions
  3. Technical Considerations:

    • Contact detection overhead
    • Complex grasp analysis
    • Multiple constraint management

Key Questions

  1. For real-time mocap-driven interaction:

    • Is a physics constraint-based approach the right direction?
    • What alternatives might work better?
  2. Regarding physics constraints:

    • Best practices for dynamic parameter adjustment?
    • Alternatives to multiple constraints for multi-finger grasping?
    • How to handle different object properties (mass, size, shape)?
  3. Edge Cases:

    • Approaches for very small/large objects?
    • Handling complex object shapes?
    • Maintaining stability with varying object properties?

Any insights from those who have worked on similar real-time physics-based interaction systems would be greatly appreciated!