A wrist-pose isolation system can infer a wrist pose (e.g., the user's hand position relative to her forearm) and can reduce wrist-induced jitter for projection casting in an XR environment. A user's projection cast can be determined as a combination of a “low-wrist contribution” component (e.g., a body-and-arm component) and a “high-wrist contribution” component (e.g., the pose of the wrist with respect to the arm). Using input from a gesture-tracking system, the contribution of the user's wrist pose to the user's current projection cast is calculated as a “wrist-contribution vector.” A projection cast direction can be determined as the interpolation of the current low-wrist contribution component and the high-wrist contribution component. This interpolation can be performed by weighting each by a specified amount and combining them.