3d-essentials

3D Essentials in Godot 4.3+

All examples target Godot 4.3+ with no deprecated APIs. GDScript is shown first, then C#.

Related skills: player-controller for CharacterBody3D movement, physics-system for 3D collision shapes and raycasting, camera-system for Camera3D follow and transitions, shader-basics for spatial shaders and post-processing, godot-optimization for 3D performance tuning, animation-system for AnimationTree and 3D animation blending.

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1. 3D Coordinate System & Core Nodes

Coordinate System

Godot uses a right-handed coordinate system with metric units (1 unit = 1 meter):

Axis	Direction	Color
X	Right	Red
Y	Up	Green
Z	Out of screen (+Z toward viewer)	Blue

Cameras and lights point along -Z by default. When a character "faces forward," they look along -Z.

Essential 3D Nodes

Node	Purpose
Node3D	Base transform node — position, rotation, scale
MeshInstance3D	Displays a mesh with a material
Camera3D	Required to render 3D — perspective or orthogonal
DirectionalLight3D	Sun/moon — parallel rays, cheapest light
OmniLight3D	Point light — emits in all directions
SpotLight3D	Cone light — flashlights, spotlights
WorldEnvironment	Sky, fog, tonemap, post-processing
Decal	Projected texture onto surfaces
GPUParticles3D	GPU-driven particle effects
CSGBox3D etc.	Constructive Solid Geometry — prototyping
GridMap	3D tile-based level building

Minimal 3D Scene

World (Node3D)
├── Camera3D
├── DirectionalLight3D
├── WorldEnvironment
├── MeshInstance3D (floor)
└── MeshInstance3D (player model)

---

2. Materials

StandardMaterial3D vs ShaderMaterial

Material	Use For	Notes
StandardMaterial3D	Most 3D objects — PBR workflow	No code; Inspector-driven
ORMMaterial3D	Same as Standard but with packed ORM texture	Occlusion+Roughness+Metallic in one texture
ShaderMaterial	Custom effects — toon, water, dissolve	Requires spatial shader code

Key StandardMaterial3D Properties

Property	Type	Description
albedo_color	Color	Base surface color
albedo_texture	Texture2D	Diffuse/albedo texture map
metallic	float	0.0 (dielectric) to 1.0 (metal)
roughness	float	0.0 (mirror) to 1.0 (matte)
emission	Color	Self-illumination color
emission_energy_multiplier	float	Emission brightness
normal_map	Texture2D	Surface detail without extra geometry
ao_texture	Texture2D	Ambient occlusion map
heightmap_texture	Texture2D	Ray-marched parallax depth illusion
rim	float	Edge lighting (micro-fur scattering)
clearcoat	float	Transparent secondary coat (car paint)

Transparency Modes

Mode	Performance	Shadows	Use For
Disabled	Fastest	Yes	Fully opaque objects
Alpha	Slow	No	Semi-transparent glass, water
Alpha Scissor	Fast	Yes	Binary cutout (leaves, fences)
Alpha Hash	Medium	Yes	Dithered transparency (hair)
Depth Pre-Pass	Medium	Partial	Mostly opaque with transparent edges

Setting Materials from Code

GDScript

@onready var mesh: MeshInstance3D = $MeshInstance3D

func _ready() -> void:
    var mat := StandardMaterial3D.new()
    mat.albedo_color = Color(0.8, 0.2, 0.2)
    mat.metallic = 0.3
    mat.roughness = 0.7
    mesh.material_override = mat

func flash_emissive() -> void:
    var mat: StandardMaterial3D = mesh.material_override
    mat.emission_enabled = true
    mat.emission = Color.WHITE
    mat.emission_energy_multiplier = 3.0
    var tween := create_tween()
    tween.tween_property(mat, "emission_energy_multiplier", 0.0, 0.3)
    tween.tween_callback(func(): mat.emission_enabled = false)

C#

private MeshInstance3D _mesh;

public override void _Ready()
{
    _mesh = GetNode<MeshInstance3D>("MeshInstance3D");
    var mat = new StandardMaterial3D();
    mat.AlbedoColor = new Color(0.8f, 0.2f, 0.2f);
    mat.Metallic = 0.3f;
    mat.Roughness = 0.7f;
    _mesh.MaterialOverride = mat;
}

public void FlashEmissive()
{
    var mat = _mesh.MaterialOverride as StandardMaterial3D;
    mat.EmissionEnabled = true;
    mat.Emission = Colors.White;
    mat.EmissionEnergyMultiplier = 3.0f;
    var tween = CreateTween();
    tween.TweenProperty(mat, "emission_energy_multiplier", 0.0f, 0.3);
    tween.TweenCallback(Callable.From(() => mat.EmissionEnabled = false));
}

Material Instancing

When multiple MeshInstance3D nodes share the same material, changing one affects all. To make a per-instance copy:

# In _ready() — creates an independent copy of the material
mesh.material_override = mesh.material_override.duplicate()

_mesh.MaterialOverride = (Material)_mesh.MaterialOverride.Duplicate();

---

3. Lighting

Light Types Comparison

Light	Shape	Shadows	Cost	Max Visible
DirectionalLight3D	Parallel rays	PSSM	Cheapest	8 (Forward+)
OmniLight3D	Sphere	Cube/Dual Paraboloid	Medium	512 clustered*
SpotLight3D	Cone	Single texture	Cheap	512 clustered*

*Forward+ shares 512 clustered element slots among omni lights, spot lights, decals, and reflection probes.

Light Properties

GDScript

@onready var sun: DirectionalLight3D = $DirectionalLight3D

func _ready() -> void:
    sun.light_color = Color(1.0, 0.95, 0.9)
    sun.light_energy = 1.0
    sun.shadow_enabled = true

    # Directional shadow quality
    sun.directional_shadow_mode = DirectionalLight3D.SHADOW_PARALLEL_4_SPLITS
    sun.directional_shadow_max_distance = 100.0

C#

private DirectionalLight3D _sun;

public override void _Ready()
{
    _sun = GetNode<DirectionalLight3D>("DirectionalLight3D");
    _sun.LightColor = new Color(1.0f, 0.95f, 0.9f);
    _sun.LightEnergy = 1.0f;
    _sun.ShadowEnabled = true;

    _sun.DirectionalShadowMode = DirectionalLight3D.ShadowMode.Parallel4Splits;
    _sun.DirectionalShadowMaxDistance = 100.0f;
}

Dynamic Point Light

func create_explosion_light(pos: Vector3) -> void:
    var light := OmniLight3D.new()
    light.light_color = Color(1.0, 0.6, 0.2)
    light.light_energy = 4.0
    light.omni_range = 10.0
    light.omni_attenuation = 2.0
    light.position = pos
    add_child(light)

    var tween := create_tween()
    tween.tween_property(light, "light_energy", 0.0, 0.5)
    tween.tween_callback(light.queue_free)

public void CreateExplosionLight(Vector3 pos)
{
    var light = new OmniLight3D();
    light.LightColor = new Color(1.0f, 0.6f, 0.2f);
    light.LightEnergy = 4.0f;
    light.OmniRange = 10.0f;
    light.OmniAttenuation = 2.0f;
    light.Position = pos;
    AddChild(light);

    var tween = CreateTween();
    tween.TweenProperty(light, "light_energy", 0.0f, 0.5);
    tween.TweenCallback(Callable.From(light.QueueFree));
}

Shadow Configuration Tips

Setting	Effect	Recommendation
shadow_bias	Prevents self-shadowing (shadow acne)	Start at 0.1, increase if acne visible
shadow_normal_bias	Better acne fix than regular bias	Prefer this over shadow_bias
directional_shadow_max_distance	Limits shadow range from camera	Lower = better quality; 50–100m typical
Shadow map resolution	Project Settings > Rendering > Lights and Shadows	2048 for perf, 4096 for quality
shadow_blur	Softens shadow edges	1.0–2.0 for gentle softness

Light Bake Modes

Mode	Description	Use For
Disabled	Not included in lightmap baking; fully real-time (default)	Moving lights, player flashlight
Static	Fully baked into lightmaps — no runtime cost	Architecture, terrain, fixed lights
Dynamic	Indirect light baked, direct light stays real-time	Lights that change color/intensity

---

4. Environment & Post-Processing

WorldEnvironment Setup

World (Node3D)
├── WorldEnvironment     ← holds Environment + CameraAttributes resources
├── DirectionalLight3D
├── Camera3D
└── ...

Set the Environment resource on WorldEnvironment and the Camera Attributes for exposure/DOF.

Sky Options

Sky Material	Description	Use For
PanoramaSkyMaterial	360° HDR panorama image	Realistic environments
ProceduralSkyMaterial	Generated sky with color gradients	Quick prototyping
PhysicalSkyMaterial	Physics-based atmosphere + sun	Outdoor day/night cycles

GDScript

func setup_environment() -> void:
    var env := Environment.new()

    # Sky
    var sky := Sky.new()
    var sky_mat := ProceduralSkyMaterial.new()
    sky_mat.sky_top_color = Color(0.4, 0.6, 1.0)
    sky_mat.sky_horizon_color = Color(0.7, 0.8, 1.0)
    sky_mat.ground_bottom_color = Color(0.2, 0.15, 0.1)
    sky.sky_material = sky_mat
    env.sky = sky
    env.background_mode = Environment.BG_SKY

    # Tonemap
    env.tonemap_mode = Environment.TONE_MAP_FILMIC
    env.tonemap_exposure = 1.0

    # Ambient light from sky
    env.ambient_light_source = Environment.AMBIENT_SOURCE_SKY

    $WorldEnvironment.environment = env

C#

public void SetupEnvironment()
{
    var env = new Godot.Environment();

    var sky = new Sky();
    var skyMat = new ProceduralSkyMaterial();
    skyMat.SkyTopColor = new Color(0.4f, 0.6f, 1.0f);
    skyMat.SkyHorizonColor = new Color(0.7f, 0.8f, 1.0f);
    skyMat.GroundBottomColor = new Color(0.2f, 0.15f, 0.1f);
    sky.SkyMaterial = skyMat;
    env.Sky = sky;
    env.BackgroundMode = Godot.Environment.BGMode.Sky;

    env.TonemapMode = Godot.Environment.ToneMapper.Filmic;
    env.TonemapExposure = 1.0f;

    env.AmbientLightSource = Godot.Environment.AmbientSource.Sky;

    GetNode<WorldEnvironment>("WorldEnvironment").Environment = env;
}

Tonemap Modes

Mode	Character	Best For
Linear	Clips brights — blown-out look	Debug, deliberately flat look
Reinhard	Simple curve, preserves brights	General use
Filmic	Film-like contrast	Cinematic games
ACES	High contrast with desaturation	Realistic/photographic
AgX	Maintains hue as brightness increases	Physically accurate lighting

Post-Processing Effects (Inspector)

Configure these on the Environment resource — no shader code needed:

Effect	Description	Renderer Support
Glow	Bloom/glow on bright surfaces	All
SSAO	Screen-space ambient occlusion	Forward+ only
SSIL	Screen-space indirect lighting	Forward+ only
SSR	Screen-space reflections	Forward+ only
SDFGI	Real-time GI for large scenes	Forward+ only
DOF	Depth of field blur (via CameraAttributes)	All
Fog	Depth and height fog	All
Adjustments	Brightness, contrast, saturation, color correction	All
Auto Exposure	Adaptive exposure (via CameraAttributes)	Forward+, Mobile

Glow Pipeline and AgX Controls (Godot 4.6+)

Godot 4.6 changes the order of the post-processing pipeline: Glow now runs before tonemapping (previously it ran after). This is physically more correct — glow should operate on HDR values before they are tone-mapped to LDR. The result is that bright emissive surfaces produce more natural-looking bloom.

Upgrade impact: Projects upgrading from 4.5 to 4.6 may notice a visible change in glow appearance. If your glow looks more intense or differently colored after upgrading, re-tune glow_intensity, glow_bloom, and glow_hdr_threshold on your Environment resource.

Godot 4.6 also adds two new controls to the AgX tonemapper:

Property	Description
tonemap_white	White point — the luminance at which the scene clips to pure white
tonemap_contrast	Contrast of the AgX sigmoid curve

var env: Environment = $WorldEnvironment.environment
env.tonemap_mode = Environment.TONE_MAP_AGX
# New AgX controls (Godot 4.6+)
env.tonemap_white = 1.0       # default; increase for brighter highlights
env.tonemap_contrast = 1.0    # default; increase for more contrast

var env = GetNode<WorldEnvironment>("WorldEnvironment").Environment;
env.TonemapMode = Godot.Environment.ToneMapper.Agx;
// New AgX controls (Godot 4.6+)
env.TonemapWhite = 1.0f;
env.TonemapContrast = 1.0f;

When to use AgX: AgX maintains hue as brightness increases, which avoids the "neon burn" artefact common with ACES on saturated emissives. The new white and contrast controls let you match a specific look reference.

Screen-Space Reflections — Quality Upgrade (Godot 4.6+)

SSR in Godot 4.6 has been redesigned for higher quality at reduced GPU cost. The WorldEnvironment SSR settings (ssr_enabled, ssr_max_steps, ssr_fade_in, ssr_fade_out, ssr_depth_tolerance) remain unchanged — the improvement is automatic for all existing projects that upgrade to 4.6.

If you previously disabled SSR due to performance concerns, it is worth re-enabling after upgrading to 4.6 and re-profiling.

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5. Global Illumination

GI Methods Comparison

Method	Quality	Performance	Dynamic	Renderer	Use For
None (ambient)	Low	Free	Yes	All	Simple/stylized games
ReflectionProbe	Medium	Low	Optional	All	Localized reflections
LightmapGI	High	Free at runtime	No	Forward+	Static scenes (archviz)
VoxelGI	High	High	Yes	Forward+	Small-medium dynamic scenes
SDFGI	Medium-High	Medium	Yes	Forward+	Large open-world scenes

ReflectionProbe

Captures the surrounding environment into a cubemap for reflections on nearby objects.

Room (Node3D)
├── ReflectionProbe      ← extents cover the room
├── MeshInstance3D (walls)
└── MeshInstance3D (shiny floor)

@onready var probe: ReflectionProbe = $ReflectionProbe

func _ready() -> void:
    probe.size = Vector3(10.0, 4.0, 10.0)  # cover the room
    probe.update_mode = ReflectionProbe.UPDATE_ONCE  # bake once, free at runtime

public override void _Ready()
{
    var probe = GetNode<ReflectionProbe>("ReflectionProbe");
    probe.Size = new Vector3(10.0f, 4.0f, 10.0f);
    probe.UpdateMode = ReflectionProbe.UpdateModeEnum.Once;
}

LightmapGI (Baked)

Best quality, zero runtime cost. Requires UV2 on meshes (auto-generated on import).

1. Add a LightmapGI node to the scene
2. Set all static lights to Bake Mode: Static
3. Set all static meshes to GI Mode: Static in the GeometryInstance3D section
4. Select LightmapGI → click Bake Lightmaps in the toolbar
5. Baked data is saved as a LightmapGIData resource — commit it with your project

SDFGI (Real-Time)

Enable on the Environment resource — no nodes needed:

var env: Environment = $WorldEnvironment.environment
env.sdfgi_enabled = true
env.sdfgi_cascades = 4
env.sdfgi_use_occlusion = true

var env = GetNode<WorldEnvironment>("WorldEnvironment").Environment;
env.SdfgiEnabled = true;
env.SdfgiCascades = 4;
env.SdfgiUseOcclusion = true;

Specular Occlusion from Ambient Light (Godot 4.5+)

Godot 4.5 automatically computes specular occlusion from the ambient light probe when baked global illumination (SDFGI, VoxelGI, or LightmapGI) is active. This prevents unrealistically bright specular highlights in areas that receive little or no indirect light — a common artifact when GI and specular are not coordinated.

No API change is required. The improvement is automatic whenever a GI method that bakes an irradiance probe is enabled:

GI Method	Specular Occlusion
None / ambient color only	No specular occlusion
ReflectionProbe	No specular occlusion
LightmapGI	Automatic (Godot 4.5+)
VoxelGI	Automatic (Godot 4.5+)
SDFGI	Automatic (Godot 4.5+)

When to use: If your scene uses LightmapGI, VoxelGI, or SDFGI and has metallic or low-roughness surfaces, upgrade to 4.5 and re-bake to see improved specular quality in occluded areas (under eaves, inside crevices, in corners).

C# uses the same GI API — specular occlusion is renderer-driven and requires no code change.

Bent Normal Maps (Godot 4.5+)

Bent normal maps encode the mean unoccluded direction from each texel — the average direction toward open sky across the hemisphere. When assigned to the Bent Normal slot on StandardMaterial3D, Godot uses this information to improve indirect lighting directionality and specular occlusion accuracy. The result is more realistic ambient lighting on complex surfaces like cloth, carved stone, or organic shapes.

Inspector setup:

1. In StandardMaterial3D, enable Bent Normal → assign your bent normal texture
2. The texture should be in tangent space (standard baked format from Marmoset, Substance, or xNormal)

@onready var mesh: MeshInstance3D = $MeshInstance3D

func _ready() -> void:
    var mat := mesh.get_surface_override_material(0) as StandardMaterial3D
    if mat == null:
        mat = StandardMaterial3D.new()
    mat.bent_normal_enabled = true
    mat.bent_normal_texture = preload("res://textures/rock_bent_normal.png")
    mesh.set_surface_override_material(0, mat)

private MeshInstance3D _mesh;

public override void _Ready()
{
    _mesh = GetNode<MeshInstance3D>("MeshInstance3D");
    var mat = _mesh.GetSurfaceOverrideMaterial(0) as StandardMaterial3D
        ?? new StandardMaterial3D();
    mat.BentNormalEnabled = true;
    mat.BentNormalTexture = GD.Load<Texture2D>("res://textures/rock_bent_normal.png");
    _mesh.SetSurfaceOverrideMaterial(0, mat);
}

Note: Bent normal maps have the most visible impact on materials that combine low roughness or high metallic values with baked GI. On fully rough dielectric surfaces the benefit is subtler.

When to use: Use bent normals on hero assets (characters, key props) where you have the budget to bake them. Skip them on background geometry.

---

6. Fog

Depth & Height Fog (Environment)

Simple fog configured on the Environment resource:

GDScript

var env: Environment = $WorldEnvironment.environment

# Depth fog — increases with distance from camera
env.fog_enabled = true
env.fog_light_color = Color(0.7, 0.75, 0.8)
env.fog_density = 0.01

# Height fog — thicker below a certain Y level
env.fog_height = 0.0
env.fog_height_density = 0.5

# Sun scattering — tints fog with directional light color
env.fog_sun_scatter = 0.3

C#

var env = GetNode<WorldEnvironment>("WorldEnvironment").Environment;
env.FogEnabled = true;
env.FogLightColor = new Color(0.7f, 0.75f, 0.8f);
env.FogDensity = 0.01f;
env.FogHeight = 0.0f;
env.FogHeightDensity = 0.5f;
env.FogSunScatter = 0.3f;

Volumetric Fog (Forward+ only)

Realistic fog that interacts with lights and casts volumetric shadows.

Enable on the Environment:

env.volumetric_fog_enabled = true
env.volumetric_fog_density = 0.05
env.volumetric_fog_albedo = Color(0.9, 0.9, 0.9)
env.volumetric_fog_emission = Color(0.0, 0.0, 0.0)
env.volumetric_fog_length = 64.0
env.volumetric_fog_temporal_reprojection_enabled = true

var env = GetNode<WorldEnvironment>("WorldEnvironment").Environment;
env.VolumetricFogEnabled = true;
env.VolumetricFogDensity = 0.05f;
env.VolumetricFogAlbedo = new Color(0.9f, 0.9f, 0.9f);
env.VolumetricFogEmission = new Color(0.0f, 0.0f, 0.0f);
env.VolumetricFogLength = 64.0f;
env.VolumetricFogTemporalReprojectionEnabled = true;

FogVolume (Localized Fog)

Create fog in specific areas (caves, steam vents, magic effects):

Scene
├── WorldEnvironment (volumetric_fog_enabled = true, density = 0.0)
└── FogVolume
    shape = Box
    size = Vector3(5, 3, 5)
    material = FogMaterial (density = 1.0)

func create_fog_cloud(pos: Vector3) -> void:
    var fog := FogVolume.new()
    fog.shape = RenderingServer.FOG_VOLUME_SHAPE_ELLIPSOID
    fog.size = Vector3(4.0, 2.0, 4.0)
    fog.position = pos

    var mat := FogMaterial.new()
    mat.density = 0.5
    mat.albedo = Color(0.8, 0.85, 0.9)
    fog.material = mat

    add_child(fog)

public void CreateFogCloud(Vector3 pos)
{
    var fog = new FogVolume();
    fog.Shape = RenderingServer.FogVolumeShape.Ellipsoid;
    fog.Size = new Vector3(4.0f, 2.0f, 4.0f);
    fog.Position = pos;

    var mat = new FogMaterial();
    mat.Density = 0.5f;
    mat.Albedo = new Color(0.8f, 0.85f, 0.9f);
    fog.Material = mat;

    AddChild(fog);
}

Set global volumetric_fog_density to 0.0 and use FogVolume nodes to place fog only where needed. This gives full control without blanket fog everywhere.

---

7. Decals

Decals project textures onto surfaces without modifying the underlying mesh. Use for bullet holes, blood splatters, footprints, ground markings.

Scene Setup

World
├── MeshInstance3D (floor)
└── Decal
    size = Vector3(1, 0.5, 1)   ← Y controls projection depth
    texture_albedo = footprint.png
    texture_normal = footprint_normal.png

Spawning Decals from Code

GDScript

func spawn_bullet_hole(hit_pos: Vector3, hit_normal: Vector3) -> void:
    var decal := Decal.new()
    decal.size = Vector3(0.3, 0.2, 0.3)
    decal.texture_albedo = preload("res://textures/bullet_hole.png")
    decal.position = hit_pos

    # Orient decal to project along the hit surface normal
    # Decals project along -Y, so rotate to align -Y with -hit_normal
    if hit_normal.abs() != Vector3.UP:
        decal.look_at(hit_pos - hit_normal, Vector3.UP)
        decal.rotate_object_local(Vector3.RIGHT, PI / 2.0)
    # For floor/ceiling hits (normal is UP or DOWN), default orientation works

    # Fade and cleanup
    decal.distance_fade_enabled = true
    decal.distance_fade_begin = 20.0
    decal.distance_fade_length = 5.0

    get_parent().add_child(decal)

    # Remove after 30 seconds
    get_tree().create_timer(30.0).timeout.connect(decal.queue_free)

C#

public void SpawnBulletHole(Vector3 hitPos, Vector3 hitNormal)
{
    var decal = new Decal();
    decal.Size = new Vector3(0.3f, 0.2f, 0.3f);
    decal.TextureAlbedo = GD.Load<Texture2D>("res://textures/bullet_hole.png");
    decal.Position = hitPos;

    if (hitNormal.Abs() != Vector3.Up)
    {
        decal.LookAt(hitPos - hitNormal, Vector3.Up);
        decal.RotateObjectLocal(Vector3.Right, Mathf.Pi / 2.0f);
    }

    decal.DistanceFadeEnabled = true;
    decal.DistanceFadeBegin = 20.0f;
    decal.DistanceFadeLength = 5.0f;

    GetParent().AddChild(decal);

    GetTree().CreateTimer(30.0f).Timeout += decal.QueueFree;
}

Decal Limits

Renderer	Max Decals
Forward+	512 clustered elements (shared with lights, probes)
Mobile	8 per mesh resource
Compatibility	Limited by max renderable elements

---

8. Optimization — LOD, Culling, MultiMesh

Mesh LOD (Automatic)

Godot auto-generates LOD levels on import for glTF, Blend, Collada, and FBX files. No manual setup needed.

Control LOD aggressiveness:

# Per-object LOD bias (GeometryInstance3D property)
# > 1.0 = keep high detail longer, < 1.0 = switch to low detail sooner
$MeshInstance3D.lod_bias = 1.5

GetNode<MeshInstance3D>("MeshInstance3D").LodBias = 1.5f;

Global LOD threshold: Project Settings > Rendering > Mesh LOD > LOD Change > Threshold Pixels (default 1.0 — perceptually lossless).

Visibility Ranges (Manual LOD)

For custom LOD with different meshes at different distances:

# Close-up: full-detail tree (0–30m)
$TreeDetailed.visibility_range_begin = 0.0
$TreeDetailed.visibility_range_end = 30.0
$TreeDetailed.visibility_range_fade_mode = GeometryInstance3D.VISIBILITY_RANGE_FADE_SELF

# Far: billboard impostor (25–100m, with crossfade overlap)
$TreeBillboard.visibility_range_begin = 25.0
$TreeBillboard.visibility_range_end = 100.0
$TreeBillboard.visibility_range_fade_mode = GeometryInstance3D.VISIBILITY_RANGE_FADE_SELF

Occlusion Culling

Prevents rendering objects hidden behind walls/large geometry.

Setup:

1. Enable: Project Settings > Rendering > Occlusion Culling > Use Occlusion Culling
2. Add an OccluderInstance3D node to your scene
3. Select it → click Bake Occluders in the 3D toolbar
4. Exclude dynamic objects via Bake > Cull Mask (assign them to different visual layers)

Only bake occluders from static geometry. Moving OccluderInstance3D nodes at runtime forces expensive BVH rebuilds.

MultiMeshInstance3D

Render thousands of identical meshes (grass, trees, debris) in a single draw call.

GDScript

func spawn_grass(positions: PackedVector3Array) -> void:
    var mm := MultiMesh.new()
    mm.transform_format = MultiMesh.TRANSFORM_3D
    mm.mesh = preload("res://meshes/grass_blade.tres")
    mm.instance_count = positions.size()

    for i in positions.size():
        var xform := Transform3D()
        xform.origin = positions[i]
        # Random rotation around Y
        xform = xform.rotated(Vector3.UP, randf() * TAU)
        # Random scale variation
        var s := randf_range(0.8, 1.2)
        xform = xform.scaled(Vector3(s, s, s))
        mm.set_instance_transform(i, xform)

    var mmi := MultiMeshInstance3D.new()
    mmi.multimesh = mm
    add_child(mmi)

C#

public void SpawnGrass(Vector3[] positions)
{
    var mm = new MultiMesh();
    mm.TransformFormat = MultiMesh.TransformFormatEnum.Transform3D;
    mm.Mesh = GD.Load<Mesh>("res://meshes/grass_blade.tres");
    mm.InstanceCount = positions.Length;

    for (int i = 0; i < positions.Length; i++)
    {
        var xform = Transform3D.Identity;
        xform.Origin = positions[i];
        xform = xform.Rotated(Vector3.Up, (float)GD.RandRange(0, Mathf.Tau));
        float s = (float)GD.RandRange(0.8, 1.2);
        xform = xform.Scaled(new Vector3(s, s, s));
        mm.SetInstanceTransform(i, xform);
    }

    var mmi = new MultiMeshInstance3D();
    mmi.Multimesh = mm;
    AddChild(mmi);
}

---

9. Renderer Comparison

Feature	Forward+	Mobile	Compatibility
SSAO / SSIL / SSR	Yes	No	No
Volumetric Fog	Yes	No	No
SDFGI	Yes	No	No
LightmapGI	Yes	Yes	Yes
VoxelGI	Yes	No	No
Glow / Bloom	Yes	Yes	Yes
Max Omni+Spot per mesh	512 clustered	8+8	8+8 (adjustable)
Target Hardware	Desktop/Console	Mobile/Mid-range	Low-end/WebGL

Choose in Project Settings > Rendering > Renderer > Rendering Method.

Rule of thumb: Start with Forward+ for desktop. Switch to Mobile for mobile targets. Use Compatibility only for web or very low-end hardware.

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10. Common Pitfalls

Symptom	Cause	Fix
3D scene is completely black	No Camera3D or no lights in scene	Add Camera3D + DirectionalLight3D + WorldEnvironment
Objects appear dark despite lighting	No ambient light or sky	Set Environment ambient_light_source to Sky or Color
Shadow acne (striped shadows)	Shadow bias too low	Increase shadow_normal_bias (preferred over shadow_bias)
Peter-panning (shadows detached)	Shadow bias too high	Lower shadow_bias; use shadow_normal_bias instead
Shadows pop in/out	directional_shadow_max_distance too high	Lower to 50–100m; quality improves as range shrinks
Material looks flat / no reflections	Missing ReflectionProbe or Sky	Add ReflectionProbe or set Environment reflected light to Sky
Decals don't appear	Y extent too small or wrong cull mask	Increase Decal Y size; check cull mask matches target layer
Transparency sorting artifacts	Overlapping transparent meshes	Use Alpha Scissor/Hash where possible; avoid layered transparency
SDFGI shows light leaking	Thin walls or small geometry	Thicken walls; increase SDFGI cascade count
Volumetric fog not visible	Wrong renderer (Mobile/Compatibility)	Switch to Forward+ renderer
MultiMesh instances invisible	instance_count set after transforms	Set instance_count before calling set_instance_transform()

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11. Implementation Checklist

• Scene has Camera3D, at least one light source, and WorldEnvironment
• Environment has a sky material (procedural or HDR panorama) for ambient and reflected light
• Tonemap mode is set (Filmic or ACES for realistic look, AgX for physically accurate)
• DirectionalLight3D has shadows enabled with shadow_normal_bias tuned to prevent acne
• directional_shadow_max_distance is set to the minimum needed (50–100m typical)
• Static geometry uses StandardMaterial3D with appropriate PBR textures (albedo, normal, roughness, metallic)
• Transparent materials use Alpha Scissor or Alpha Hash instead of Alpha where possible (performance + shadows)
• ReflectionProbes are placed in rooms/areas with reflective surfaces
• GI method chosen based on project needs (LightmapGI for static, SDFGI for large dynamic, VoxelGI for small dynamic)
• Mesh LOD is enabled on import (default for glTF/Blend — verify OBJ files)
• Occlusion culling is enabled and baked for scenes with heavy occlusion (indoor, urban)
• MultiMeshInstance3D is used for instanced geometry (grass, trees, props) instead of individual nodes
• Renderer matches target platform (Forward+ desktop, Mobile mobile, Compatibility web)
• Projects using LightmapGI/VoxelGI/SDFGI take advantage of automatic specular occlusion by upgrading to Godot 4.5+ (no API change required)
• Hero assets with complex surface detail use bent normal maps in the StandardMaterial3D Bent Normal slot for improved indirect lighting (Godot 4.5+)
• After upgrading to Godot 4.6, glow settings are re-tuned if appearance has changed (glow now runs before tonemapping)
• AgX tonemap_white and tonemap_contrast are adjusted when using AgX tonemapper for precise look control (Godot 4.6+)