Chapter 3: Basic Modeling Techniques

Haiyue1/3/24About 5 min

Chapter 3: Basic Modeling Techniques

Learning Objectives

Master the creation and editing of basic geometric primitives
Learn vertex, edge, and face editing operations
Understand mesh topology
Master basic tools like extrude, inset, and bevel
Learn to use modifiers for parametric modeling

Detailed Knowledge Points

3.1 Polygon Modeling Basics

3.1.1 Mesh Structure

A polygon mesh is composed of three basic elements:

Vertices - Points
    ↓
Edges - Lines connecting two vertices
    ↓
Faces - Polygons enclosed by edges

Mesh Properties:

Vertices: Basic points defining the shape, with position information
Edges: Connect vertices, defining the shape's outline
Faces: Enclosed areas, used for rendering and display

Face Types

Tris: The most basic face, efficient for rendering
Quads: Preferred for modeling, easy to subdivide and edit
N-gons: Faces with 5 or more sides, generally to be avoided

3.1.2 Basic Primitives

Adding Basic Primitives:

Shift + A → Mesh  # Open the mesh menu

List of basic primitives:
- Plane: 4 vertices
- Cube: 8 vertices
- Circle: Default 32 vertices
- UV Sphere: Latitude/longitude sphere
- Ico Sphere: Icosahedron sphere (triangular faces)
- Cylinder: Default 32 sides
- Cone
- Torus

Primitive Parameter Settings:

# After adding, adjust parameters in the bottom-left panel or by pressing F9
Vertices: Number of vertices (for circles, cylinders, etc.)
Radius: Radius
Depth: Depth (cylinder height)
Location: Position
Rotation: Rotation

3.2 Edit Mode Basics

3.2.1 Toggling Edit Mode

Tab  # Object Mode ↔ Edit Mode

# Switching selection types in Edit Mode
1  # Vertex select mode (or Ctrl+Tab menu)
2  # Edge select mode
3  # Face select mode

# Combined selection modes
Shift + 1/2/3  # Enable multiple selection modes simultaneously

3.2.2 Basic Selection Operations

Selection Tools:

# Basic selection
Left-click  # Select a single element
Shift + Left-click  # Add/remove from selection
A  # Select all
Alt + A  # Deselect all
Ctrl + I  # Invert selection

# Extend selection
Ctrl + +  # Grow selection
Ctrl + -  # Shrink selection

# Loop selection
Alt + Left-click  # Select edge loop
Ctrl + Alt + Left-click  # Select face ring

Select Similar:

Shift + G  # Select similar menu
- Vertex Groups
- Co-planar
- Area: Similar area
- Sides: Similar number of sides
- Material: Same material

3.3 Basic Editing Tools

3.3.1 Extrude Tool

Extrude is one of the most important tools in modeling:

E  # Extrude selected faces/edges/vertices

# Extrude variations
E + X/Y/Z  # Extrude along an axis
E + S  # Extrude and scale

# Special extrude
Alt + E  # Extrude menu
- Extrude Region
- Extrude Individual Faces
- Extrude to Cursor

Extrude Application Example:

# Make a simple house
1. Add a cube
2. Tab to enter Edit Mode
3. 3 to switch to face select mode
4. Select the top face
5. E to extrude, Z to constrain vertically, enter 0.5
6. S to scale to 0.8 to create the roof edge
7. E again to extrude up by 0.3 to create the roof

3.3.2 Inset Faces

I  # Inset faces tool

# Inset options
I + I  # Inset individual faces
I + O  # Outset

# Operations during inset
- Mouse move: Adjust inset distance
- Ctrl: Enable uniform mode
- O: Toggle outset

3.3.3 Bevel Tool

Ctrl + B  # Bevel selected edges/vertices

# Bevel controls
- Mouse move: Adjust bevel size
- Scroll wheel: Increase/decrease segments
- Ctrl: Enable snapping
- Shift: Precise adjustment

Bevel Application:

# Create a rounded cube
1. Select all edges of the cube (Alt + A, then 2 for edge mode, A)
2. Ctrl + B to bevel
3. Use the scroll wheel to increase segments to 3-4
4. Adjust the size to a suitable value

3.4 Advanced Editing Tools

3.4.1 Loop Cut and Knife

Loop Cut:

Ctrl + R  # Loop cut tool
- Mouse move: Select cut position
- Scroll wheel: Increase number of cuts
- Confirm: Left-click
- Slide: Mouse move to adjust position

Knife Tool:

K  # Knife tool
- Left-click: Create cut point
- Enter: Confirm cut
- Esc: Cancel

K + C  # Constrain knife cut (e.g., only 45-degree angles)

3.4.2 Merge and Dissolve

Merge Vertices:

Alt + M  # Merge menu
- At Center
- At Cursor
- Collapse
- At First/Last

Dissolve Elements:

Ctrl + X  # Delete/dissolve menu
- Vertices
- Dissolve Vertices
- Edge Loops
- Faces

3.4.3 Subdivide and Smooth

Subdivide:

# Right-click menu or toolbar
Subdivide  # Subdivide selected faces
- Number of Cuts
- Smoothness
- Fractal

Smooth:

# Right-click menu
Smooth  # Smooth vertices
Shade Smooth  # Smooth shading
Shade Flat  # Flat shading

3.5 Modifier System

3.5.1 Modifier Concept

Modifiers are non-destructive modeling tools that allow for real-time preview of effects:

Original Mesh → Modifier 1 → Modifier 2 → Final Result

Modifier Features:

Non-destructive editing
Can be stacked
Real-time preview
Parameters can be adjusted at any time

3.5.2 Common Modeling Modifiers

Mirror Modifier:

# Add Mirror modifier
Properties Panel → Modifier Properties → Add Modifier → Mirror

Main parameters:
- Axis: Mirror axis (X/Y/Z)
- Bisect: Bisect the original mesh
- Merge: Merge vertices on the centerline

Array Modifier:

# Array parameters
Count: Number of copies
Relative Offset
Constant Offset
Object Offset

Subdivision Surface Modifier:

# Subdivision parameters
Levels Viewport
Render
Type: Catmull-Clark (smooth) / Simple (not smooth)

3.6 Modeling Workflow

3.6.1 Blockout Modeling

# Step 1: Create basic shapes
1. Start with simple primitives
2. Use extrude to create the basic silhouette
3. Don't focus on details, just the overall form

# Step 2: Refine the shape
4. Add necessary loop cuts
5. Adjust vertex positions
6. Use bevel to add details

# Step 3: Optimize topology
7. Ensure quads are dominant
8. Maintain good edge flow
9. Avoid n-gons and triangles

3.6.2 Modeling with Reference Images

# Set up reference images
1. Shift + A → Empty → Image
2. Load reference image in the Properties panel
3. Adjust transparency and position
4. Set up different reference images in multiple views

# Model according to reference
5. Start modeling from the side view
6. Gradually adjust in different views
7. Maintain correspondence with the reference image

3.7 Practical Exercises

Exercise 1: Basic Furniture Modeling

Exercise Goal

Master the comprehensive use of basic modeling tools

# Make a simple chair
# Seat creation:
1. Add a cube
2. S + Z + 0.1 (flatten for the seat)
3. S + X + 0.8, S + Y + 0.8 (adjust seat size)

# Backrest creation:
4. E to extrude the top face
5. S + Y + 0.1 (thin for the backrest)
6. G + Z + 0.8 (move the backrest up)

# Leg creation:
7. Enter Edit Mode, select the four corner vertices of the bottom face
8. E to extrude downwards
9. S + 0.1 (shrink for the legs)

Exercise 2: Organic Shape Modeling

# Make a simple vase
1. Add a cylinder (Vertices: 12)
2. Tab to enter Edit Mode
3. Alt + A to deselect all, then 3 (face select mode)
4. Select the top face, Delete
5. 2 to switch to edge select mode
6. Alt + Left-click to select the top edge loop
7. Ctrl + R to add multiple loop cuts (scroll wheel to adjust count to 5-6)
8. Select edge loops at different heights
9. S to scale different edge loops to create the vase silhouette
10. Select the bottom edge loop, E to extrude, S + 0 to merge and create the bottom

Exercise 3: Modifier Application

Important Notes

The order of modifiers is important
Be cautious before applying modifiers
Pay attention to the object's center position when mirror modeling

# Make a symmetrical ornament
1. Add a cube
2. Tab to enter Edit Mode
3. Select and delete the vertices on the right half
4. Add a Mirror modifier (Axis: X)
5. Model on one side, the other side mirrors automatically
6. Use extrude and bevel to create details
7. Apply the Mirror modifier when finished

# Create an array ornament
8. Select the finished ornament
9. Add an Array modifier
10. Set Count to 5, adjust the offset distance
11. Create a row of ornaments

3.8 Topology Best Practices

3.8.1 Characteristics of Good Topology

Quad-first:

✓ Quad mesh:
□─□─□
│ │ │
□─□─□
│ │ │
□─□─□

✗ Messy topology:
△─□─◇
│/│\│
□─◇─△

Edge Flow Direction:

Edges should follow the natural flow of the shape
Circular areas use radial edge flow
Muscle and deformation areas need appropriate edge flow

3.8.2 Topology Optimization Techniques

# Reduce n-gons
1. Select the n-gon face
2. Mesh → Faces → Triangulate Faces
3. Manually merge adjacent edges and vertices

# Increase resolution
1. Select the area to be subdivided
2. Right-click → Subdivide
3. Or use loop cuts to add edge loops

# Retopology
1. Create a new mesh over the original model
2. Use Retopo features to align to the original model's surface
3. Maintain a good quad structure

3.9 Common Modeling Shortcuts

Tool	Shortcut	Description
Extrude	E	Extrude face/edge/vertex
Inset	I	Inset face
Bevel	Ctrl + B	Bevel edge/vertex
Loop Cut	Ctrl + R	Loop cut tool
Knife	K	Knife tool
Merge	Alt + M	Merge vertices
Separate	P	Separate to new object
Join	J	Join vertices
Fill	F	Fill face
Subdivide	Ctrl + 1-4	Apply subdivision levels

Modeling Tool Summary

In the Edit Mode toolbar:

Selection Tools:
- Select Box (B)
- Select Circle (C)
- Lasso Select

Basic Tools:
- Extrude (E)
- Inset (I)
- Bevel (Ctrl+B)
- Knife (K)
- Loop Cut (Ctrl+R)

Advanced Tools:
- PolyBuild: Interactive modeling
- Edge Split
- Spin: Spin duplicate
- Screw: Screw tool

Learning Suggestions

Start Simple: Master basic tools before learning advanced techniques
Understand Topology: Good topology is the foundation for subsequent operations
Practice a Lot: Modeling requires a lot of practice to become proficient
Reference Reality: Observe the shapes and structures of real objects
Keep it Clean: Regularly clean up unused vertices and edges

By completing this chapter, you should be able to:

Use basic modeling tools proficiently
Understand the importance of mesh topology
Create moderately complex models
Use the modifier system appropriately

These skills are the foundation for all complex modeling work and must be practiced repeatedly until mastered.