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)

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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

| 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 & 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](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 |

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

Light Properties

| Property | Type | Default | Notes | |---|---|---|---| | light_color | Color | white | Drive day/night with a Tween or Environment.sun_position | | light_energy | float | 1.0 | HDR; values >1 are valid | | shadow_enabled | bool | false | Big perf hit when enabled | | directional_shadow_mode | enum | 4 splits | ORTHOGONAL / PARALLEL_2_SPLITS / PARALLEL_4_SPLITS | | directional_shadow_max_distance | float | 100 m | Lower = sharper shadows |

sun.light_color = Color(1.0, 0.95, 0.9)
sun.shadow_enabled = true
sun.directional_shadow_mode = DirectionalLight3D.SHADOW_PARALLEL_4_SPLITS
sun.directional_shadow_max_distance = 100.0

sun.LightColor = new Color(1.0f, 0.95f, 0.9f);
sun.ShadowEnabled = true;
sun.DirectionalShadowMode = DirectionalLight3D.ShadowMode.Parallel4Splits;
sun.DirectionalShadowMaxDistance = 100.0f;

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](references/materials-and-lighting-recipes.md#dynamic-point-light) for the full GDScript and C# recipe.

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 |

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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](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).

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

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](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](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.

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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 ambientlightsource 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

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Source & license

This open-source skill is cataloged on AgentStack and links to its original source — we do not rehost the code.

• Author: jame581
• Source: jame581/GodotPrompter
• License: MIT

Install and usage instructions live in the source repository linked above.