12 files changed, 41 insertions, 24 deletions
diff --git a/doc/classes/Array.xml b/doc/classes/Array.xml
index a294967fc9..234949277a 100644
--- a/doc/classes/Array.xml
+++ b/doc/classes/Array.xml
@@ -14,6 +14,12 @@
 		array[2] = "Three"
 		print(array[-2]) # Three.
 		[/codeblock]
+		Arrays can be concatenated using the [code]+[/code] operator:
+		[codeblock]
+		var array1 = ["One", 2]
+		var array2 = [3, "Four"]
+		print(array1 + array2) # ["One", 2, 3, "Four"]
+		[/codeblock]
 		Arrays are always passed by reference.
 	</description>
 	<tutorials>
diff --git a/doc/classes/Engine.xml b/doc/classes/Engine.xml
index 8cdb9c1c3f..45c153b6dc 100644
--- a/doc/classes/Engine.xml
+++ b/doc/classes/Engine.xml
@@ -147,10 +147,10 @@
 			If [code]true[/code], it is running inside the editor. Useful for tool scripts.
 		</member>
 		<member name="iterations_per_second" type="int" setter="set_iterations_per_second" getter="get_iterations_per_second" default="60">
-			The number of fixed iterations per second (for fixed process and physics).
+			The number of fixed iterations per second. This controls how often physics simulation and [method Node._physics_process] methods are run. This value should generally always be set to [code]60[/code] or above, as Godot doesn't interpolate the physics step. As a result, values lower than [code]60[/code] will look stuttery. This value can be increased to make input more reactive or work around tunneling issues, but keep in mind doing so will increase CPU usage.
 		</member>
 		<member name="physics_jitter_fix" type="float" setter="set_physics_jitter_fix" getter="get_physics_jitter_fix" default="0.5">
-			Controls how much physic ticks are synchronized  with real time. For 0 or less, the ticks are synchronized. Such values are recommended for network games, where clock synchronization matters. Higher values cause higher deviation of in-game clock and real clock, but allows to smooth out framerate jitters. The default value of 0.5 should be fine for most; values above 2 could cause the game to react to dropped frames with a noticeable delay and are not recommended.
+			Controls how much physics ticks are synchronized with real time. For 0 or less, the ticks are synchronized. Such values are recommended for network games, where clock synchronization matters. Higher values cause higher deviation of in-game clock and real clock, but allows to smooth out framerate jitters. The default value of 0.5 should be fine for most; values above 2 could cause the game to react to dropped frames with a noticeable delay and are not recommended.
 		</member>
 		<member name="target_fps" type="int" setter="set_target_fps" getter="get_target_fps" default="0">
 			The desired frames per second. If the hardware cannot keep up, this setting may not be respected. A value of 0 means no limit.
diff --git a/doc/classes/Navigation.xml b/doc/classes/Navigation.xml
index 0000ca6bd5..93170bca4a 100644
--- a/doc/classes/Navigation.xml
+++ b/doc/classes/Navigation.xml
@@ -4,7 +4,7 @@
 		Mesh-based navigation and pathfinding node.
 	</brief_description>
 	<description>
-		Provides navigation and pathfinding within a collection of [NavigationMesh]es. These will be automatically collected from child [NavigationMeshInstance] nodes. In addition to basic pathfinding, this class also assists with aligning navigation agents with the meshes they are navigating on.
+		Provides navigation and pathfinding within a collection of [NavigationMesh]es. These will be automatically collected from child [NavigationRegion] nodes. In addition to basic pathfinding, this class also assists with aligning navigation agents with the meshes they are navigating on.
 	</description>
 	<tutorials>
 	</tutorials>
diff --git a/doc/classes/Navigation2D.xml b/doc/classes/Navigation2D.xml
index 0d016a3210..dcbfbc2350 100644
--- a/doc/classes/Navigation2D.xml
+++ b/doc/classes/Navigation2D.xml
@@ -4,7 +4,7 @@
 		2D navigation and pathfinding node.
 	</brief_description>
 	<description>
-		Navigation2D provides navigation and pathfinding within a 2D area, specified as a collection of [NavigationPolygon] resources. These are automatically collected from child [NavigationPolygonInstance] nodes.
+		Navigation2D provides navigation and pathfinding within a 2D area, specified as a collection of [NavigationPolygon] resources. These are automatically collected from child [NavigationRegion2D] nodes.
 	</description>
 	<tutorials>
 	</tutorials>
diff --git a/doc/classes/NavigationPolygon.xml b/doc/classes/NavigationPolygon.xml
index da291b7337..b0f77dff83 100644
--- a/doc/classes/NavigationPolygon.xml
+++ b/doc/classes/NavigationPolygon.xml
@@ -11,7 +11,7 @@
 		var outline = PackedVector2Array([Vector2(0, 0), Vector2(0, 50), Vector2(50, 50), Vector2(50, 0)])
 		polygon.add_outline(outline)
 		polygon.make_polygons_from_outlines()
-		$NavigationPolygonInstance.navpoly = polygon
+		$NavigationRegion2D.navpoly = polygon
 		[/codeblock]
 		Using [method add_polygon] and indices of the vertices array.
 		[codeblock]
@@ -20,7 +20,7 @@
 		polygon.set_vertices(vertices)
 		var indices = PackedInt32Array(0, 3, 1)
 		polygon.add_polygon(indices)
-		$NavigationPolygonInstance.navpoly = polygon
+		$NavigationRegion2D.navpoly = polygon
 		[/codeblock]
 	</description>
 	<tutorials>
diff --git a/doc/classes/NavigationMeshInstance.xml b/doc/classes/NavigationRegion.xml
index 75bd62e278..41fac70654 100644
--- a/doc/classes/NavigationMeshInstance.xml
+++ b/doc/classes/NavigationRegion.xml
@@ -1,10 +1,10 @@
 <?xml version="1.0" encoding="UTF-8" ?>
-<class name="NavigationMeshInstance" inherits="Spatial" version="4.0">
+<class name="NavigationRegion" inherits="Spatial" version="4.0">
 	<brief_description>
-		An instance of a [NavigationMesh].
+		A region of the navigation map.
 	</brief_description>
 	<description>
-		An instance of a [NavigationMesh]. It tells the [Navigation] node what can be navigated and what cannot, based on the [NavigationMesh] resource. This should be a child of a [Navigation] node.
+		A region of the navigation map. It tells the [Navigation] node what can be navigated and what cannot, based on the [NavigationMesh] resource. This should be a child of a [Navigation] node (even not a direct child).
 	</description>
 	<tutorials>
 	</tutorials>
@@ -19,7 +19,7 @@
 	</methods>
 	<members>
 		<member name="enabled" type="bool" setter="set_enabled" getter="is_enabled" default="true">
-			Determines if the [NavigationMeshInstance] is enabled or disabled.
+			Determines if the [NavigationRegion] is enabled or disabled.
 		</member>
 		<member name="navmesh" type="NavigationMesh" setter="set_navigation_mesh" getter="get_navigation_mesh">
 			The [NavigationMesh] resource to use.
diff --git a/doc/classes/NavigationPolygonInstance.xml b/doc/classes/NavigationRegion2D.xml
index 34c6b09859..aef114e1db 100644
--- a/doc/classes/NavigationPolygonInstance.xml
+++ b/doc/classes/NavigationRegion2D.xml
@@ -1,5 +1,5 @@
 <?xml version="1.0" encoding="UTF-8" ?>
-<class name="NavigationPolygonInstance" inherits="Node2D" version="4.0">
+<class name="NavigationRegion2D" inherits="Node2D" version="4.0">
 	<brief_description>
 	</brief_description>
 	<description>
diff --git a/doc/classes/PhysicsServer.xml b/doc/classes/PhysicsServer.xml
index 592d3d8e4e..c9f4accee2 100644
--- a/doc/classes/PhysicsServer.xml
+++ b/doc/classes/PhysicsServer.xml
@@ -1467,7 +1467,7 @@
 			If [code]set[/code] there is a linear motor on this axis that targets a specific velocity.
 		</constant>
 		<constant name="SHAPE_PLANE" value="0" enum="ShapeType">
-			The [Shape] is a [PlaneShape].
+			The [Shape] is a [WorldMarginShape].
 		</constant>
 		<constant name="SHAPE_RAY" value="1" enum="ShapeType">
 			The [Shape] is a [RayShape].
diff --git a/doc/classes/ProjectSettings.xml b/doc/classes/ProjectSettings.xml
index 236931f877..a2c6ed34e0 100644
--- a/doc/classes/ProjectSettings.xml
+++ b/doc/classes/ProjectSettings.xml
@@ -968,10 +968,12 @@
 			Enables [member Viewport.physics_object_picking] on the root viewport.
 		</member>
 		<member name="physics/common/physics_fps" type="int" setter="" getter="" default="60">
-			Frames per second used in the physics. Physics always needs a fixed amount of frames per second.
+			The number of fixed iterations per second. This controls how often physics simulation and [method Node._physics_process] methods are run.
+			[b]Note:[/b] This property is only read when the project starts. To change the physics FPS at runtime, set [member Engine.iterations_per_second] instead.
 		</member>
 		<member name="physics/common/physics_jitter_fix" type="float" setter="" getter="" default="0.5">
 			Fix to improve physics jitter, specially on monitors where refresh rate is different than the physics FPS.
+			[b]Note:[/b] This property is only read when the project starts. To change the physics FPS at runtime, set [member Engine.physics_jitter_fix] instead.
 		</member>
 		<member name="rendering/environment/default_clear_color" type="Color" setter="" getter="" default="Color( 0.3, 0.3, 0.3, 1 )">
 			Default background clear color. Overridable per [Viewport] using its [Environment]. See [member Environment.background_mode] and [member Environment.background_color] in particular. To change this default color programmatically, use [method VisualServer.set_default_clear_color].
@@ -1035,23 +1037,28 @@
 			Lower-end override for [member rendering/quality/intended_usage/framebuffer_allocation] on mobile devices, due to performance concerns or driver support.
 		</member>
 		<member name="rendering/quality/reflection_atlas/reflection_count" type="int" setter="" getter="" default="64">
+			Number of cubemaps to store in the reflection atlas. The number of [ReflectionProbe]s in a scene will be limited by this amount. A higher number requires more VRAM.
 		</member>
-		<member name="rendering/quality/reflection_atlas/reflection_size" type="int" setter="" getter="" default="256">
+		<member name="rendering/quality/reflection_atlas/reflection_size" type="int" setter="" getter="" default="128">
+			Size of cubemap faces for [ReflectionProbe]s. A higher number requires more VRAM and may make reflection probe updating slower.
 		</member>
 		<member name="rendering/quality/reflection_atlas/reflection_size.mobile" type="int" setter="" getter="" default="128">
+			Lower-end override for [member rendering/quality/reflection_atlas/reflection_size] on mobile devices, due to performance concerns or driver support.
+		</member>
+		<member name="rendering/quality/reflections/fast_filter_high_quality" type="bool" setter="" getter="" default="false">
+			Use a higher quality variant of the fast filtering algorithm. Significantly slower than using default quality, but results in smoother reflections. Should only be used when the scene is especially detailed.
 		</member>
 		<member name="rendering/quality/reflections/ggx_samples" type="int" setter="" getter="" default="1024">
+			Sets the number of samples to take when using importance sampling for [Sky]s and [ReflectionProbe]s. A higher value will result in smoother, higher quality reflections, but increases time to calculate radiance maps. In general, fewer samples are needed for simpler, low dynamic range environments while more samples are needed for HDR environments and environments with a high level of detail.
 		</member>
 		<member name="rendering/quality/reflections/ggx_samples.mobile" type="int" setter="" getter="" default="128">
-		</member>
-		<member name="rendering/quality/reflections/ggx_samples_realtime" type="int" setter="" getter="" default="64">
-		</member>
-		<member name="rendering/quality/reflections/ggx_samples_realtime.mobile" type="int" setter="" getter="" default="16">
+			Lower-end override for [member rendering/quality/reflections/ggx_samples] on mobile devices, due to performance concerns or driver support.
 		</member>
 		<member name="rendering/quality/reflections/roughness_layers" type="int" setter="" getter="" default="6">
+			Limits the number of layers to use in radiance maps when using importance sampling. A lower number will be slightly faster and take up less VRAM.
 		</member>
 		<member name="rendering/quality/reflections/texture_array_reflections" type="bool" setter="" getter="" default="true">
-			If [code]true[/code], uses texture arrays instead of mipmaps for reflection probes and panorama backgrounds (sky). This reduces jitter noise on reflections, but costs more performance and memory.
+			If [code]true[/code], uses texture arrays instead of mipmaps for reflection probes and panorama backgrounds (sky). This reduces jitter noise and upscaling artifacts on reflections, but is significantly slower to compute and uses [member rendering/quality/reflections/roughness_layers] times more memory.
 		</member>
 		<member name="rendering/quality/reflections/texture_array_reflections.mobile" type="bool" setter="" getter="" default="false">
 			Lower-end override for [member rendering/quality/reflections/texture_array_reflections] on mobile devices, due to performance concerns or driver support.
diff --git a/doc/classes/ReflectionProbe.xml b/doc/classes/ReflectionProbe.xml
index 9c7a645fec..e138af6841 100644
--- a/doc/classes/ReflectionProbe.xml
+++ b/doc/classes/ReflectionProbe.xml
@@ -4,7 +4,7 @@
 		Captures its surroundings to create reflections.
 	</brief_description>
 	<description>
-		Capture its surroundings as a dual parabolid image, and stores versions of it with increasing levels of blur to simulate different material roughnesses.
+		Captures its surroundings as a cubemap, and stores versions of it with increasing levels of blur to simulate different material roughnesses.
 		The [ReflectionProbe] is used to create high-quality reflections at the cost of performance. It can be combined with [GIProbe]s and Screen Space Reflections to achieve high quality reflections. [ReflectionProbe]s render all objects within their [member cull_mask], so updating them can be quite expensive. It is best to update them once with the important static objects and then leave them.
 	</description>
 	<tutorials>
@@ -52,7 +52,7 @@
 	</members>
 	<constants>
 		<constant name="UPDATE_ONCE" value="0" enum="UpdateMode">
-			Update the probe once on the next frame.
+			Update the probe once on the next frame. The corresponding radiance map will be generated over the following six frames. This is slower to update than [constant UPDATE_ALWAYS] but can result in higher quality reflections.
 		</constant>
 		<constant name="UPDATE_ALWAYS" value="1" enum="UpdateMode">
 			Update the probe every frame. This is needed when you want to capture dynamic objects. However, it results in an increased render time. Use [constant UPDATE_ONCE] whenever possible.
diff --git a/doc/classes/Sky.xml b/doc/classes/Sky.xml
index 72599a323d..ba9c5ee661 100644
--- a/doc/classes/Sky.xml
+++ b/doc/classes/Sky.xml
@@ -12,6 +12,7 @@
 	</methods>
 	<members>
 		<member name="process_mode" type="int" setter="set_process_mode" getter="get_process_mode" enum="Sky.ProcessMode" default="0">
+			Sets the method for generating the radiance map from the sky. The radiance map is a cubemap with increasingly blurry versions of the sky corresponding to different levels of roughness. Radiance maps can be expensive to calculate. See [enum ProcessMode] for options.
 		</member>
 		<member name="radiance_size" type="int" setter="set_radiance_size" getter="get_radiance_size" enum="Sky.RadianceSize" default="2">
 			The [Sky]'s radiance map size. The higher the radiance map size, the more detailed the lighting from the [Sky] will be.
@@ -45,8 +46,11 @@
 			Represents the size of the [enum RadianceSize] enum.
 		</constant>
 		<constant name="PROCESS_MODE_QUALITY" value="0" enum="ProcessMode">
+			Uses high quality importance sampling to process the radiance map. In general, this results in much higher quality than [constant PROCESS_MODE_REALTIME] but takes much longer to generate. This should not be used if you plan on changing the sky at runtime.
 		</constant>
 		<constant name="PROCESS_MODE_REALTIME" value="1" enum="ProcessMode">
+			Uses the fast filtering algorithm to process the radiance map. In general this results in lower quality, but substantially faster run times.
+			[b]Note:[/b] The fast filtering algorithm is limited to 128x128 cubemaps, so [member radiance_size] must be set to [constant RADIANCE_SIZE_128].
 		</constant>
 	</constants>
 </class>
diff --git a/doc/classes/PlaneShape.xml b/doc/classes/WorldMarginShape.xml
index b40e133d00..54f76a066b 100644
--- a/doc/classes/PlaneShape.xml
+++ b/doc/classes/WorldMarginShape.xml
@@ -1,10 +1,10 @@
 <?xml version="1.0" encoding="UTF-8" ?>
-<class name="PlaneShape" inherits="Shape" version="4.0">
+<class name="WorldMarginShape" inherits="Shape" version="4.0">
 	<brief_description>
 		Infinite plane shape for 3D collisions.
 	</brief_description>
 	<description>
-		An infinite plane shape for 3D collisions. Note that the [Plane]'s normal matters; anything "below" the plane will collide with it. If the [PlaneShape] is used in a [PhysicsBody], it will cause colliding objects placed "below" it to teleport "above" the plane.
+		An infinite plane shape for 3D collisions. Note that the [Plane]'s normal matters; anything "below" the plane will collide with it. If the [WorldMarginShape] is used in a [PhysicsBody], it will cause colliding objects placed "below" it to teleport "above" the plane.
 	</description>
 	<tutorials>
 	</tutorials>
@@ -12,7 +12,7 @@
 	</methods>
 	<members>
 		<member name="plane" type="Plane" setter="set_plane" getter="get_plane" default="Plane( 0, 1, 0, 0 )">
-			The [Plane] used by the [PlaneShape] for collision.
+			The [Plane] used by the [WorldMarginShape] for collision.
 		</member>
 	</members>
 	<constants>