3d-essentials

name	3d-essentials
description	Use when working with 3D-specific systems — materials, lighting, shadows, environment, global illumination, fog, LOD, occlusion culling, and decals in Godot 4.3+

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

Godot 4.7+: GridMap exposes its internal octants for spatial queries — cell_octant_size = 8 (cells per octant, per axis) plus get_used_octants(), get_used_octants_by_item(item), get_octants_in_bounds(bounds) (includes empty octants), get_used_octants_in_bounds(bounds), get_used_cells_in_octant(octant_coords), get_used_cells_in_octant_by_item(octant_coords, item), and get_octant_coords_from_cell_coords(cell_coords). Octant and cell coordinates are Vector3i (returned in Array[Vector3i]); bounds is a local-space AABB.

Godot 4.7+: CSGShape3D gains automatic smoothing — enable autosmooth (default false) and tune smoothing_angle (default 50.0): faces meeting at an angle greater than smoothing_angle are smoothed, smaller angles stay sharp; a value below 0.1 disables all smoothing (a performance escape hatch). Children of a CSGCombiner3D are treated as a single mesh.

Minimal 3D Scene

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

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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

The PBR core: albedo_color / albedo_texture (base color), metallic (0 dielectric → 1 metal), roughness (0 mirror → 1 matte), normal_map (surface detail), ao_texture (ambient occlusion). Add emission + emission_energy_multiplier for self-illumination, heightmap_texture for parallax, rim / clearcoat for material flair.

Transparency Modes

Prefer Alpha Scissor (fast, shadowed cutouts) or Alpha Hash (dithered — hair) over plain Alpha (slow, no shadows); Depth Pre-Pass suits mostly-opaque meshes with transparent edges.

See references/materials-and-lighting-recipes.md for the comparison table.

Setting Materials from Code & Material Instancing

Create a StandardMaterial3D at runtime, assign to mesh.material_override, and drive emissive flashes via Tween. Use .duplicate() to make per-instance copies so changing one mesh's material doesn't affect others.

See references/materials-and-lighting-recipes.md for the full GDScript and C# recipes (basic material setup, emissive flash, per-instance duplicate, dynamic OmniLight3D explosion).

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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*
AreaLight3D (4.7+)	Rectangle	PCSS soft	Most expensive	—

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

Light Properties

Key knobs: light_color, light_energy (HDR — values >1 are valid), shadow_enabled (big perf hit), directional_shadow_mode, directional_shadow_max_distance (lower = sharper shadows).

See references/materials-and-lighting-recipes.md for the properties table and the GDScript + C# sun setup snippet.

AreaLight3D (Godot 4.7+)

AreaLight3D emits light from a rectangle along the node's -Z — neon tubes, screens, softbox panels — with PCSS soft shadows driven by light_size. Key properties: area_size = Vector2(1, 1) (meters), area_range = 5.0, area_attenuation = 1.0 (2.0 = physically accurate inverse square), area_normalize_energy = true (resizing keeps total output stable), optional area_texture for textured emission (Forward+/Mobile only). Mobile support is limited and Compatibility cannot cast area-light shadows; in Forward+, a single visible area light adds clustered-lighting cost to all rendered objects — reserve for cinematics or high-end targets.

See references/materials-and-lighting-recipes.md for the full property table and the GDScript + C# setup recipe.

Dynamic Point Light

Spawn an OmniLight3D at runtime, drive its energy with a tween, queue-free on completion. Common for explosions, muzzle flashes, magic effects.

See references/materials-and-lighting-recipes.md for the full GDScript and C# recipe.

Shadow Configuration & Bake Modes

Prefer shadow_normal_bias over shadow_bias against acne; keep directional_shadow_max_distance at the minimum needed (50–100 m typical). Bake modes: Disabled (fully real-time, default), Static (fully baked, no runtime cost), Dynamic (indirect baked, direct real-time).

See references/materials-and-lighting-recipes.md for the shadow-tuning table and the bake-modes table.

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4. Environment & Post-Processing

Configure global rendering — sky background, tonemapping, glow, SSR, SSAO/SSIL/SDFGI, depth-of-field — through a WorldEnvironment node holding an Environment resource. Pick a tonemap (Linear, Reinhard, Filmic, ACES, or AgX) on the Environment resource. Forward+ enables SSAO, SSIL, SSR, and SDFGI; mobile/compatibility renderers omit these.

See references/environment-and-post.md for the full setup recipes (sky options, tonemap modes, all post-processing effects, the 4.6+ glow-before-tonemapping pipeline change, AgX tonemap_white / tonemap_contrast controls, and the 4.6+ SSR quality upgrade).

Godot 4.7+: display/window/hdr/request_hdr_output (default false, promoted to a basic project setting) requests HDR display output for the main window and editor where supported, auto-switching between HDR and SDR as screens or system settings change; it forces Viewport.use_hdr_2d on for the main viewport (other SubViewports must enable it themselves). Read only at startup — toggle Window.hdr_output_requested at runtime.

⚠️ Changed in Godot 4.7: The rendering/reflections/sky_reflections/roughness_layers default changed from 7 to 8, altering sky-reflection roughness mip distribution for projects that left it at the default. Set it back to 7 to keep the 4.6 output. See the 4.7 migration guide.

5. Global Illumination

Five GI options trade quality for cost: none (ambient only) → ReflectionProbe (localized) → LightmapGI (best quality, baked) → VoxelGI (small/medium dynamic) → SDFGI (large open-world). VoxelGI/SDFGI/LightmapGI require Forward+. The 4.5+ subsections below (Specular Occlusion, Bent Normal Maps) stay inline because they apply across GI methods.

See references/global-illumination.md for the methods comparison table, ReflectionProbe scene + code recipe, LightmapGI bake workflow, and SDFGI configuration.

Specular Occlusion from Ambient Light (Godot 4.5+)

Godot 4.5+ automatically computes specular occlusion from the ambient light probe when LightmapGI, VoxelGI, or SDFGI is active. Prevents unrealistically bright speculars in areas that receive little indirect light (under eaves, inside crevices, in corners). No API change — re-bake after upgrading to see the improvement on metallic / low-roughness surfaces. ReflectionProbe alone does not provide specular occlusion.

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: In StandardMaterial3D, enable Bent Normal → assign your tangent-space bent normal texture (baked from Marmoset, Substance, or xNormal).

Most visible on: materials that combine low roughness or high metallic values with baked GI (LightmapGI / VoxelGI / SDFGI). On fully rough dielectric surfaces the benefit is subtler. Use on hero assets; skip on background geometry.

See references/materials-and-lighting-recipes.md for the runtime-assignment GDScript + C# code path (the Inspector setup above is the typical case).

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6. Fog

Three layers: depth/height fog set on WorldEnvironment.environment (cheap, all renderers), volumetric fog (Forward+ only — godrays through depth), and FogVolume nodes for localized fog effects (interior rooms, pits, atmospheric volumes).

See references/fog-recipes.md for the full GDScript and C# recipes — depth/height fog setup, volumetric fog parameters and performance notes, and FogVolume placement.

⚠️ Changed in Godot 4.7: Volumetric fog is now blended using transmittance instead of opacity, so existing volumetric fog can look different after upgrading. Enable the project setting rendering/environment/fog/use_legacy_blending (default false) to restore the previous behavior. See GH-119414.

7. Decals

Decal nodes project a texture onto whatever surfaces fall within their bounding box — bullet holes, blood splatter, ground details, signage. All renderers support decals; performance scales with overdraw and decal count.

See references/decals.md for the scene setup, runtime spawning recipe (GDScript + C#), and the per-renderer decal limits.

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8. Optimization — LOD, Culling, MultiMesh

Four tools: automatic mesh LOD (set on import or per MeshInstance3D), manual VisibilityRange for staged swaps, occlusion culling via OccluderInstance3D, and MultiMeshInstance3D for thousands of identical meshes in one draw call.

See references/lod-and-culling.md for setup recipes for each tool plus the MultiMesh runtime population example.

9. Renderer Comparison

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

Choose in Project Settings → Rendering → Renderer → Rendering Method. Rule of thumb: Forward+ for desktop, Mobile for mobile, Compatibility only for web or very low-end hardware.

Godot 4.7+: Vulkan raytracing (RenderingDevice BLAS/TLAS and raytracing pipelines) shipped experimental in 4.7 and is not yet recommended for production.

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10. Common Pitfalls

Quick symptom → cause → fix table covering black scenes, dark objects without ambient light, shadow acne and peter-panning, popping shadows, flat materials, invisible decals, transparency sorting artifacts, SDFGI light leaking, missing volumetric fog, and invisible MultiMesh instances.

See references/common-pitfalls.md for the full table.

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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+)
• After upgrading to Godot 4.7, volumetric fog and sky reflections are re-checked (fog blending and the roughness_layers default changed)