Quick answer: Godot 4 CharacterBody3D jittering vertically while airborne? Floor snap is active mid-air - clear floor_snap_length when velocity.y > 0 or set apply_floor_snap to false on jump.

Player jumps off a ledge. Mid-air the camera shakes 1-2 units vertically because move_and_slide is snapping to phantom floors.

Clear snap on jump

if velocity.y > 0.0:
    floor_snap_length = 0.0
else:
    floor_snap_length = 0.3

Snap is intended for downhill traversal. When ascending, it forces depenetration with downward geometry the body would clear naturally.

Adjust floor max angle

If snap is required, raise floor_max_angle to ~50 degrees. Snap looks for floors within this cone; a tight cone misses ramps and re-tries every frame.

Verify with debug print

Print is_on_floor() per physics tick during the airborne segment. Toggling true/false indicates phantom contacts - the bug's signature.

“Floor snap is great on slopes and a disaster in the air.”

For platformer-style controllers, write a one-line state machine: grounded -> snap on, jumping -> snap off, falling -> snap on at 0.1. Three lines, no jitter.