This article presents HapticIO, a research project aimed at advancing haptic feedback technologies for spatial input devices and controllers in Extended Reality. We present four prototypes: HapticCollider, providing ungrounded force feedback for rigid collisions in virtual tool use; MorphGrip, offering shapechanging haptic guidance for precise manual tasks; PumpVR, rendering object and avatar weight using liquid mass transfer; and MobileGravity, enabling weight simulation in mobile scenarios. Furthermore, we derive a predictive model for optimizing weight rendering through a study assessing the effects of absolute mass and weight distribution. Additionally, each system is evaluated through empirical user studies, revealing significant improvements in realism.
We discuss integrating these technologies into unified devices while addressing associated challenges.