The ONLY guaranteed solution to physics body jitter in Godot - separate your physics body from its visual representation. Works with 3D too, but smoothing is now built into Godot for 3D (not yet built in for 2D).

CharRigidBody.gd

class_name CharRigidBody extends RigidBody2D

# Your visual representation node, e.g. Sprite
export(NodePath) var visual_body_path: NodePath

# For RigidBody tweening
var physics_body_trans_last: Transform
var physics_body_trans_current: Transform
var debug: bool = true

onready var visual_body: Sprite = get_node(visual_body_path)

func _init() -> void:
	# Doing our own physics interpolation.
	if Engine.get_physics_jitter_fix() != 0.0: Engine.set_physics_jitter_fix(0.0)


func _ready() -> void:
	# Config physics tweening
	physics_body_trans_current = self.global_transform
	physics_body_trans_last = physics_body_trans_current
	visual_body.set_as_toplevel(true) # Unparent visual body transform from any parent.
	set_process_priority(100) # Process other nodes first.


func _physics_process(delta: float) -> void:
	# Store current transform for physics body.
	physics_body_trans_last = physics_body_trans_current
	physics_body_trans_current = self.global_transform


func _process(delta: float) -> void:
	# Interpolate movement for visual body.
	visual_body.global_transform = physics_body_trans_last.interpolate_with(
		physics_body_trans_current,
		Engine.get_physics_interpolation_fraction()
	)

More on the 3D implementation here: https://github.com/belzecue/godot-physics-fraction

Node composition would look like this:

RigidBody2D
\CollisionShape2D
\Sprite

The Sprite is your visual body/representation.

Hi, is this script for the sprite/visual body of the character? If so what should we code in kinematic body? Thanks for code btw..