Chapter 6: Texture Creation and UV Mapping

Learning Objectives

• Master UV unwrapping techniques and best practices
• Learn texture painting and integration with external software
• Understand texture types and their uses (diffuse, normal, roughness, etc.)
• Master texture baking techniques
• Learn texture optimization and management

Detailed Knowledge Points

6.1 UV Mapping Basics

6.1.1 UV Coordinate System Principle

3D Model Surface → UV Unwrap → 2D Texture Space

U-axis: Horizontal direction (0-1)
V-axis: Vertical direction (0-1)

The role of UV mapping:

• Establish a correspondence between the 3D surface and the 2D texture
• Control the distribution of textures on the model
• Provide a reference for texture painting

6.1.2 UV Editor Interface

# Switch to the UV Editing workspace
Workspace selection: UV Editing

Interface layout:
├── 3D Viewport (right side)
├── UV Editor (left side)
├── Image Editor
└── Properties Panel

6.2 UV Unwrapping Techniques

6.2.1 Automatic Unwrapping

# Automatic UV unwrapping
1. Select the object, enter Edit Mode
2. Select all faces (A)
3. Press U to open the UV unwrapping menu
4. Choose an unwrapping method:
   - Unwrap: Smart unwrap
   - Smart UV Project: Smart projection
   - Lightmap Pack: Lightmap packing
   - Follow Active Quads: Follow active quads
   - Cube Projection
   - Cylinder/Sphere Projection

Unwrapping Method Comparison:

Method	Use Case	Pros	Cons
Unwrap	Complex organic objects	Low distortion, preserves shape	Requires marking seams
Smart UV Project	Hard-surface objects	Automatic, no marking needed	May create too many UV islands
Cube Projection	Boxy objects	Simple and fast	Seams at edges
Cylinder Projection	Cylindrical objects	Conforms to geometry	Distortion at top/bottom

6.2.2 Manual Seam Marking

# Mark Seams
1. Enter Edit Mode, switch to edge select (2)
2. Select the edges to be used as seams
3. Shift + E to mark as seam
4. Alt + Shift + E to clear seam mark

# Seam selection principles:
- Choose less obvious edges
- Avoid setting in important detail areas
- Consider the convenience of texture painting
- Maintain a reasonable size for UV islands

6.2.3 UV Unwrapping Optimization

# UV unwrap parameter adjustment
Unwrap options:
├── Method:
│   ├── Angle Based
│   └── Conformal
├── Fill Holes
├── Correct Aspect
└── Use Subdivision Surface

# Real-time preview adjustment:
1. After unwrapping, check the result in the UV Editor
2. Adjust parameters and re-unwrap
3. Manually adjust UV vertex positions

6.3 UV Editing Tools

6.3.1 Basic Editing Operations

# UV Editor shortcuts
Selection tools:
- A: Select all
- Alt + A: Deselect all
- L: Select linked
- Ctrl + L: Select linked UV island

Transform operations:
- G: Move
- R: Rotate
- S: Scale
- E: Extrude edge

# UV island operations
- Ctrl + A: Average UV islands
- Ctrl + E: Mark seam
- P: Separate UV island
- V: Merge UV islands

6.3.2 UV Island Arrangement

# Automatic UV island arrangement
U menu → Pack Islands
Parameters:
├── Margin
├── Rotate: Allow rotation
└── Merge Overlapping

# Manual arrangement tips:
1. Allocate more UV space to important parts
2. Overlap similar parts to utilize space
3. Maintain the relative proportions of UV islands
4. Avoid stretching and distortion

6.4 Texture Painting

6.4.1 Texture Paint Mode

# Start texture painting
1. Switch to the Texture Paint workspace
2. Or select Texture Paint mode in the 3D viewport
3. Create a new image or load an existing texture

# Texture painting settings:
- Brush settings: Size, strength, falloff
- Blend mode: Mix, Multiply, Add, etc.
- Color selection: Foreground/background color
- Brush texture: Custom brush pattern

6.4.2 Brush Tools

Basic Brush Types:

Brush	Function	Use
Draw	Draw	Basic color painting
Soften	Soften	Smooth transitions
Smear	Smear	Blend colors
Clone	Clone	Copy texture area
Fill	Fill	Fill large areas with color
Mask	Mask	Protect areas

Advanced Painting Techniques:

# Multi-layer painting workflow
1. Create a base color layer
2. Add details and variations
3. Use masks to protect completed areas
4. Paint different material properties in layers

# Projection painting
1. Paint from multiple angles
2. Project from reference images
3. Use stencils and decals

6.4.3 External Software Integration

# Integration with Photoshop/GIMP
1. Export UV layout: UV Editor → UV → Export UV Layout
2. Edit in external software
3. Blender automatically updates after saving

# Real-time editing workflow:
1. Set the image editor to monitor file changes
2. Automatically reload after external modifications
3. Keep Blender and external software in sync

6.5 Texture Types Explained

6.5.1 PBR Texture Standard

Complete PBR Texture Set:

Texture map types:
├── Albedo/Diffuse: Base color
├── Normal: Normal map
├── Roughness: Roughness
├── Metallic: Metallic
├── Specular: Specular reflection
├── AO (Ambient Occlusion): Ambient occlusion
├── Height/Displacement: Height displacement
├── Opacity: Opacity
└── Emission: Emission

6.5.2 Normal Map Creation

# Generate normal map from height map
1. Create a high-resolution height texture
2. Convert using the Normal Map node
3. Or generate in external software (like CrazyBump)

# Generate normal map in Blender:
Shader Editor:
Height Texture → Bump → Normal Map → Principled BSDF

# Normal map strength control:
Normal Map node → Strength parameter (0.0-2.0)

6.6 Texture Baking

6.6.1 Baking Basics

Baking is the process of transferring detail information from a high-poly model to a texture:

# Baking process:
High-poly model → Project onto low-poly model → Generate texture map

Bake types:
├── Diffuse: Diffuse color
├── Normal: Normal information
├── AO: Ambient Occlusion
├── Roughness: Roughness
├── Displacement: Displacement
└── Combined: Combined lighting

6.6.2 Bake Settings

# Bake parameter settings
Render Properties → Bake:
├── Bake Type
├── Influence
├── Selected to Active
├── Cage Extrusion
├── Max Ray Distance
├── Margin (pixels)
└── Clear Image

# Baking preparation:
1. Prepare high-poly and low-poly models
2. Ensure the low-poly model has good UV unwrapping
3. Create a target texture image
4. Set the active texture node

6.6.3 Multi-detail Baking

# Complex baking workflow
1. Geometry detail baking:
   High-poly → Normal map

2. Material baking:
   Complex material → Simplified texture

3. Lighting baking:
   Complex lighting → Lightmap

4. Ambient occlusion baking:
   Global illumination → AO map

6.7 Texture Optimization

6.7.1 Texture Resolution Optimization

# Texture resolution selection guide
Use case classification:
├── Hero assets (main characters): 4K-8K
├── Important props: 2K-4K
├── Background objects: 1K-2K
├── Distant objects: 512-1K
└── UI/icons: Moderate as needed

# Compression and optimization:
1. Use appropriate image formats
   - PNG: Lossless, supports transparency
   - JPEG: Lossy, small file size
   - EXR: HDR, high dynamic range
2. Enable texture compression
3. Use Mip-mapping

6.7.2 Texture Set Management

# Texture Atlas
1. Combine multiple small textures into one large texture
2. Reduce the number of render calls
3. Improve render performance

Create a texture atlas:
1. Plan the texture layout
2. Adjust the UVs of each part to the corresponding area
3. Merge textures into a single image
4. Update material references

# Texture variation management:
- Create variations using texture nodes
- ColorRamp for color adjustment
- Noise to add randomness
- Mix node to combine multiple effects

6.8 Advanced Texture Techniques

6.8.1 Procedural Texture Details

# Procedural detail enhancement
Base texture + Procedural noise = Rich details

Node combination example:
Image Texture → Mix (Overlay) ← Noise Texture
     ↓
Principled BSDF

# Multi-level details:
1. Large-scale structure (main texture)
2. Medium details (noise overlay)
3. Micro details (high-frequency noise)

6.8.2 Animated Textures

# UV animated texture
1. Use the Location of the Mapping node
2. Add keyframes to animate the displacement
3. Create a flowing effect

# Procedural animation:
Noise Texture + Time driver = Dynamic texture
- Connect W input to time
- Create a flowing cloud effect
- Simulate liquid surface waves

6.9 Practical Exercises

Exercise 1: Character Head UV Unwrapping

Exercise Goal

Master UV unwrapping techniques for complex organic objects

# Character head UV unwrapping process
# Step 1: Analyze model structure
1. Identify main features: face, ears, neck
2. Plan seam positions
3. Consider the convenience of texture painting

# Step 2: Mark seams
4. Center line on the back of the head
5. Where the ears connect
6. Bottom of the neck
7. Avoid important areas on the front

# Step 3: Unwrap and adjust
8. U → Unwrap
9. Adjust proportions in the UV Editor
10. Ensure the face area is large enough
11. Distribute ears and neck reasonably

# Step 4: Final optimization
12. Pack Islands to organize the layout
13. Check for stretching and distortion
14. Export UV layout for painting

Exercise 2: Building Texture Creation

# Building exterior wall texture creation
# Step 1: UV unwrap planning
1. Unwrap in groups according to building structure
2. Use planar projection for walls
3. Unwrap details separately

# Step 2: Base texture painting
4. Paint or import a brick wall texture
5. Add stains and wear effects
6. Create details for windows and doors

# Step 3: Normal and detail maps
7. Create a normal map for brick seams
8. Add variations in surface roughness
9. Ambient occlusion to enhance depth

# Step 4: Material node setup
10. Connect each map with an Image Texture node
11. Set the correct color space
12. Adjust the strength of each map

Exercise 3: Vehicle Texture Baking

Important Notes

• Ensure high and low poly models are aligned
• Set appropriate bake parameters
• Pay attention to the Margin setting for edges

# Car model texture baking
# Step 1: Prepare models
1. High-poly sculpted model (rich in detail)
2. Low-poly game model (optimized topology)
3. Ensure both are aligned

# Step 2: UV preparation
4. UV unwrap the low-poly model
5. Optimize UV island distribution
6. Maximize texture utilization

# Step 3: Bake settings
7. Select the high-poly model, then the low-poly model
8. Enable Selected to Active
9. Set Cage Extrusion: 0.1
10. Max Ray Distance: 0.5

# Step 4: Multi-pass baking
11. Normal bake
12. AO bake
13. Curvature bake
14. Color ID bake

# Step 5: Post-processing
15. Process the baked results in Photoshop
16. Paint additional details
17. Create wear and stain effects

6.10 Texture Creation Shortcuts

Operation	Shortcut	Description
UV Unwrap	U	UV unwrap menu
Mark Seam	Shift + E	Mark selected edge as seam
Clear Seam	Alt + Shift + E	Clear seam mark
Select Linked	L	Select linked UV island
Separate UV	P	Separate UVs of selected faces
Pack Islands	Ctrl + P	Automatically arrange UV islands
Reset UV	Alt + R	Reset UV transform
Follow Active Quads	U → Follow Active Quads	Special unwrap method

Learning Suggestions

1. Understand UV Principles: Master the concept of 3D to 2D mapping
2. Practice Unwrapping: Different types of objects require different unwrapping strategies
3. Focus on Efficiency: Plan UV layouts reasonably to improve texture utilization
4. Learn Baking: Master the transfer of details from high-poly to low-poly
5. Combine Tools: Make good use of the advantages of Blender and external software

By completing this chapter, you should be able to:

• Perform various types of UV unwrapping proficiently
• Master texture painting and editing techniques
• Understand and apply texture baking techniques
• Optimize texture performance and quality

Texture creation is an important part of 3D art, and good textures can greatly enhance the realism and artistic effect of a model.