godot-3d-materials（戈多 3d 材料）

3D Materials

Expert guidance for PBR materials and StandardMaterial3D in Godot.

NEVER Do

• NEVER use separate metallic/roughness/AO textures — Use ORM packing (1 RGB texture with Occlusion/Roughness/Metallic channels) to save texture slots and memory.
• NEVER forget to enable normal_enabled — Normal maps don't work unless you set normal_enabled = true. Silent failure is common.
• NEVER use TRANSPARENCY_ALPHA for cutout materials — Use TRANSPARENCY_ALPHA_SCISSOR or TRANSPARENCY_ALPHA_HASH instead. Full alpha blending is expensive and causes sorting issues.
• NEVER set metallic = 0.5 — Materials are either metallic (1.0) or dielectric (0.0). Values between are physically incorrect except for rust/dirt transitions.
• NEVER use emission without HDR — Emission values > 1.0 only work with HDR rendering enabled in Project Settings.
• NEVER use transparent materials for large environmental surfaces — Transparent objects cannot rely on the Z-buffer for early fragment rejection, resulting in massive overdraw. If only a tiny part of a mesh is transparent, split the mesh into two surfaces: one opaque, one transparent.
• NEVER create hundreds of slightly varied StandardMaterial3D resources if performance is dropping — Godot minimizes GPU state changes by automatically reusing the underlying shader for materials that share the exact same configuration flags (checkboxes). Try to group your material configurations.
• NEVER attempt to fix Z-fighting strictly by moving objects further apart — Floating-point precision degrades over distance. To fix flickering textures, increase your Camera3D's Near plane property and decrease the Far property to compress the precision range.
• NEVER use unique Material resources per MeshInstance3D — This breaks draw call batching. Use 'Instance Uniforms' to vary parameters while keeping a single shared material.
• NEVER use Decals on dynamic moving actors without a Cull Mask — Bullet holes should not stick to the player's face as they walk over them. Mask out character layers.

Available Scripts

MANDATORY: Read the appropriate script before implementing the corresponding pattern.

material_fx.gd

Runtime material property animation for damage effects, dissolve, and texture swapping. Use for dynamic material state changes.

pbr_material_builder.gd

Runtime PBR material creation with ORM textures and triplanar mapping.

organic_material.gd

Subsurface scattering and rim lighting setup for organic surfaces (skin, leaves). Use for realistic character or vegetation materials.

triplanar_world.gdshader

Triplanar projection shader for terrain without UV mapping. Blends textures based on surface normals. Use for cliffs, caves, or procedural terrain.

pbr_orm_packer.gd

Expert PBR resource utility. Packs Ambient Occlusion, Roughness, and Metallic into a single ORM texture to optimize VRAM and draw calls.

vertex_wind_sway.gdshader

High-performance GPU-driven foliage animation. Uses vertex world coordinates and vertex color weight painting to simulate wind without skeletons.

triplanar_world_projection.gdshader

UV-less environment mapping. Projects textures along X/Y/Z axes for organic blending over complex rocks and terrain.

subsurface_scattering_setup.gd

Configuring realistic organic materials. Covers Skin Mode, Transmittance, and depth scattering settings for Forward+ rendering.

instance_uniform_batching.gdshader

Architecture pattern for high-speed batching. Allows 10,000 meshes to share one material while maintaining unique colors or health states via instance uniforms.

decal_placer_expert.gd

Dynamic 3D decal system with cull masking and life-cycle management for impact effects.

transparency_sorting_fix.gd

Solving visual artifacts using Alpha Hash and Depth Prepass strategies.

shader_state_manager.gd

Clean pattern for toggling shader-based visual states (Frozen, Burned) on multiple entities.

depth_precision_fix.gd

Camera-side fix for Z-fighting and texture flickering in large-scale worlds.

material_batcher.gd

Global override system to ensure environmental meshes draw in optimized, state-locked batches.

StandardMaterial3D Basics

PBR Texture Setup

# Create physically-based material
var mat := StandardMaterial3D.new()

# Albedo (base color)
mat.albedo_texture = load("res://textures/wood_albedo.png")
mat.albedo_color = Color.WHITE  # Tint multiplier

# Normal map (surface detail)
mat.normal_enabled = true  # CRITICAL: Must enable first
mat.normal_texture = load("res://textures/wood_normal.png")
mat.normal_scale = 1.0  # Bump strength

# ORM Texture (R=Occlusion, G=Roughness, B=Metallic)
mat.orm_texture = load("res://textures/wood_orm.png")

# Alternative: Separate textures (less efficient)
# mat.roughness_texture = load("res://textures/wood_roughness.png")
# mat.metallic_texture = load("res://textures/wood_metallic.png")
# mat.ao_texture = load("res://textures/wood_ao.png")

# Apply to mesh
$MeshInstance3D.material_override = mat

Metallic vs Roughness

Metal Workflow

# Pure metal (steel, gold, copper)
mat.metallic = 1.0
mat.roughness = 0.2  # Polished metal
mat.albedo_color = Color(0.8, 0.8, 0.8)  # Metal tint

# Rough metal (iron, aluminum)
mat.metallic = 1.0
mat.roughness = 0.7

Dielectric Workflow

# Non-metal (wood, plastic, stone)
mat.metallic = 0.0
mat.roughness = 0.6  # Typical for wood
mat.albedo_color = Color(0.6, 0.4, 0.2)  # Brown wood

# Glossy plastic
mat.metallic = 0.0
mat.roughness = 0.1  # Very smooth

Transition Materials (Rust/Dirt)

# Use texture to blend metal/non-metal
mat.metallic_texture = load("res://rust_mask.png")
# White areas (1.0) = metal
# Black areas (0.0) = rust (dielectric)

Transparency Modes

Decision Matrix

Alpha Scissor (Cutout)

# For leaves, grass, fences
mat.transparency = BaseMaterial3D.TRANSPARENCY_ALPHA_SCISSOR
mat.alpha_scissor_threshold = 0.5  # Pixels < 0.5 alpha = discarded
mat.albedo_texture = load("res://leaf.png")  # Must  have alpha channel

# Enable backface culling for performance
mat.cull_mode = BaseMaterial3D.CULL_BACK

Alpha Hash (Dithered)

# For smooth fade-outs without sorting issues
mat.transparency = BaseMaterial3D.TRANSPARENCY_ALPHA_HASH
mat.alpha_hash_scale = 1.0  # Dither pattern scale

# Animate fade
var tween := create_tween()
tween.tween_property(mat, "albedo_color:a", 0.0, 1.0)

Alpha Blend (Full Transparency)

# For glass, water (expensive)
mat.transparency = BaseMaterial3D.TRANSPARENCY_ALPHA
mat.blend_mode = BaseMaterial3D.BLEND_MODE_MIX

# Disable depth writing for correct blending
mat.depth_draw_mode = BaseMaterial3D.DEPTH_DRAW_DISABLED
mat.cull_mode = BaseMaterial3D.CULL_DISABLED  # Show both sides

Advanced Features

Emission (Glowing Materials)

mat.emission_enabled = true
mat.emission = Color(1.0, 0.5, 0.0)  # Orange glow
mat.emission_energy_multiplier = 2.0  # Brightness (HDR)
mat.emission_texture = load("res://lava_emission.png")

# Animated emission
func _process(delta: float) -> void:
    mat.emission_energy_multiplier = 1.0 + sin(Time.get_ticks_msec() * 0.005) * 0.5

Rim Lighting (Fresnel)

mat.rim_enabled = true
mat.rim = 1.0  # Intensity
mat.rim_tint = 0.5  # How much albedo affects rim color

Clearcoat (Car Paint)

mat.clearcoat_enabled = true
mat.clearcoat = 1.0  # Layer strength
mat.clearcoat_roughness = 0.1  # Glossy top layer

Anisotropy (Brushed Metal)

mat.anisotropy_enabled = true
mat.anisotropy = 1.0  # Directional highlights
mat.anisotropy_flowmap = load("res://brushed_flow.png")

Texture Channel Packing

ORM Texture (Recommended)

# External tool (GIMP, Substance, Python script):
# Combine 3 grayscale textures into 1 RGB:
# R channel = Ambient Occlusion (bright = no occlusion)
# G channel = Roughness (bright = rough)
# B channel = Metallic (bright = metal)

# In Godot:
mat.orm_texture = load("res://textures/material_orm.png")
# This replaces ao_texture, roughness_texture, and metallic_texture!

Custom Packing

# If using custom channel assignments:
mat.roughness_texture_channel = BaseMaterial3D.TEXTURE_CHANNEL_GREEN
mat.metallic_texture_channel = BaseMaterial3D.TEXTURE_CHANNEL_BLUE

Shader Conversion

When to Convert to ShaderMaterial

• Need custom effects (dissolve, vertex displacement)
• StandardMaterial3D limitations hit
• Shader optimizations (remove unused features)

Conversion Workflow

# 1. Create StandardMaterial3D with all settings
var std_mat := StandardMaterial3D.new()
std_mat.albedo_color = Color.RED
std_mat.metallic = 1.0
std_mat.roughness = 0.2

# 2. Convert to ShaderMaterial
var shader_mat := ShaderMaterial.new()
shader_mat.shader = load("res://custom_shader.gdshader")

# 3. Transfer parameters manually
shader_mat.set_shader_parameter("albedo", std_mat.albedo_color)
shader_mat.set_shader_parameter("metallic", std_mat.metallic)
shader_mat.set_shader_parameter("roughness", std_mat.roughness)

Material Variants (Godot 4.0+)

Efficient Material Reuse

# Base material (shared)
var base_red_metal := StandardMaterial3D.new()
base_red_metal.albedo_color = Color.RED
base_red_metal.metallic = 1.0

# Variant 1: Rough
var rough_variant := base_red_metal.duplicate()
rough_variant.roughness = 0.8

# Variant 2: Smooth
var smooth_variant := base_red_metal.duplicate()
smooth_variant.roughness = 0.1

# Note: Use resource_local_to_scene for per-instance tweaks

Performance Optimization

Material Batching

# ✅ GOOD: Reuse materials across meshes
const SHARED_STONE := preload("res://materials/stone.tres")

func _ready() -> void:
    for wall in get_tree().get_nodes_in_group("stone_walls"):
        wall.material_override = SHARED_STONE
    # All walls batched in single draw call

# ❌ BAD: Unique material per mesh
func _ready() -> void:
    for wall in get_tree().get_nodes_in_group("stone_walls"):
        var mat := StandardMaterial3D.new()  # New material!
        mat.albedo_color = Color(0.5, 0.5, 0.5)
        wall.material_override = mat
    # Each wall is separate draw call

Texture Atlasing

# Combine multiple materials into one texture atlas
# Then use UV offsets to select regions

# material_atlas.gd
extends StandardMaterial3D

func set_atlas_region(tile_x: int, tile_y: int, tiles_per_row: int) -> void:
    var tile_size := 1.0 / tiles_per_row
    uv1_offset = Vector3(tile_x * tile_size, tile_y * tile_size, 0)
    uv1_scale = Vector3(tile_size, tile_size, 1)

Edge Cases

Normal Maps Not Working

# Problem: Forgot to enable
mat.normal_enabled = true  # REQUIRED

# Problem: Wrong texture import settings
# In Import tab: Texture → Normal Map = true

Texture Seams on Models

# Problem: Mipmaps causing seams
# Solution: Disable mipmaps for tightly-packed UVs
# Import → Mipmaps → Generate = false

Material Looks Flat

# Problem: Missing normal map or roughness variation
# Solution: Add normal map + roughness texture

mat.normal_enabled = true
mat.normal_texture = load("res://normal.png")
mat.roughness_texture = load("res://roughness.png")

Common Material Presets

# Glass
func create_glass() -> StandardMaterial3D:
    var mat := StandardMaterial3D.new()
    mat.transparency = BaseMaterial3D.TRANSPARENCY_ALPHA
    mat.albedo_color = Color(1, 1, 1, 0.2)
    mat.metallic = 0.0
    mat.roughness = 0.0
    mat.refraction_enabled = true
    mat.refraction_scale = 0.05
    return mat

# Gold
func create_gold() -> StandardMaterial3D:
    var mat := StandardMaterial3D.new()
    mat.albedo_color = Color(1.0, 0.85, 0.3)
    mat.metallic = 1.0
    mat.roughness = 0.3
    return mat

Expert Techniques & Optimizations

1. LOD Transitions using Pixel Dither

When utilizing Hierarchical Level of Detail (HLOD) or Visibility Ranges to fade objects out at a distance, standard alpha blending causes severe performance hits due to overlapping transparent bounds. Instead, configure the Distance Fade mode on your material to Pixel Dither. This provides a perceptually smooth fade while remaining entirely within the high-performance opaque pipeline.

2. Stencil Buffers (Godot 4.5+)

Use the Stencil Buffer directly in StandardMaterial3D. This allows you to easily render outlines or X-ray effects for objects hidden behind walls without needing to write custom shaders for basic effects.

3. AR Shadow Overlay Shader

If you are developing an AR game, you might want virtual shadows to appear on real-world camera feeds. Instead of standard blending, use Godot's built-in shadow_to_opacity render mode in a spatial shader.

shader_type spatial;
// shadow_to_opacity makes the material invisible when lit,
// but opaque (dark) when it receives a shadow from another 3D object.
render_mode blend_mix, depth_draw_opaque, cull_back, shadow_to_opacity;

void fragment() {
    // The surface color is black; opacity will be driven by incoming shadows
    ALBEDO = vec3(0.0, 0.0, 0.0);
}

Reference

• Master Skill: godot-master