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Lesson 3-04 – Extrude and Revolve

🌀 Lesson 3-4: Extrude and Revolve

Transform 2D shapes into complex 3D objects using powerful modeling tools like EXTRUDE and REVOLVE.

📚 What You’ll Learn

By the end of this lesson, you’ll be able to:

  • Use the EXTRUDE command to convert 2D shapes into 3D solids
  • Use the REVOLVE command to spin profiles around an axis
  • Control direction, taper, and height of extrusion
  • Visualize and modify extruded and revolved forms
  • Understand key differences between extrusion and revolution modeling

🧰 Tools You’ll Use

Tool / CommandDescription
EXTRUDEProjects 2D profiles along a path to create a 3D solid
REVOLVESpins a 2D shape around an axis to form a solid
UCS & PLANAlign drawing orientation for accurate modeling
VISUALSTYLESChange between realistic, wireframe, and shaded views
SLICE / SECTION(Optional) Use to inspect extruded/revolved interiors

❗ Why It Matters

Extrusion and revolution are core techniques in 3D modeling. Most mechanical parts, architectural components, and product designs begin as simple 2D sketches that are then extruded or revolved. Mastery of these tools allows you to build everything from beams and posts to bowls and turbine blades.

🧱 Understanding Extrude and Revolve

FeatureEXTRUDEREVOLVE
InputClosed 2D polyline/shapeClosed 2D shape
ResultPushes shape into 3D formRotates shape around axis
Ideal ForBeams, slabs, ducts, panelsBowls, wheels, vases, rings
AxisDefined by direction vectorDefined by two axis points
TaperCan apply taper angleConstant profile unless edited

🔧 Using the Commands

EXTRUDE Example

  1. Draw a closed polyline (e.g. rectangle or circle)
  2. Activate the EXTRUDE command
  3. Select the shape
  4. Enter a height (e.g. 5 units)
  5. Press Enter – the shape becomes a 3D solid

💡 Optional: Add a taper angle to create conical shapes.

REVOLVE Example

  1. Draw a profile (e.g. half-circle or custom shape)
  2. Type REVOLVE
  3. Select the shape
  4. Define the axis of rotation by two points
  5. Enter rotation angle (usually 360 for full object)

💡 Use REVOLVE to make symmetrical solids like bottles or knobs.

🔍 Practice Activity

Objective: Model a simple drinking cup using EXTRUDE and REVOLVE.

Instructions:

  1. Draw a 2D circle (base of the cup)
  2. Use EXTRUDE to give it height (e.g. 6 units)
  3. Draw a profile of a cup side (half-outline) on a vertical plane
  4. Use REVOLVE around vertical axis to create a smooth cup form
  5. Apply SUBTRACT (optional) to hollow the cup

🛠️ Best Practices

TipWhy It’s Useful
Use PLAN view before creating profilesEnsures shape is flat and clean
Avoid open polylinesCommands require closed loops for solid generation
Work in consistent UCSKeeps modeling orientation predictable
Save original 2D profilesUseful for later revisions or alternate approaches

🗺️ Visualizing Models

Use the following tools to analyze your solid:

ToolUse
3DORBITRotate around your object for inspection
HIDERemove obscured lines for clarity
SECTIONPLANECut open the object to view inside
SHADEMODESwitch between wireframe, hidden, realistic

📌 Quick Review

CommandDescription
EXTRUDEPushes 2D profile into 3D space
REVOLVESpins 2D profile around axis
TAPEROptional setting for extrude
AXISKey element in revolve command
UCSEnsure correct orientation before drawing

📦 Sample Use Cases

  • EXTRUDE a rectangle for a wall or beam
  • EXTRUDE a circle for a pipe or column
  • REVOLVE a curve for a vase, bowl, or tire
  • Combine both to create more complex geometry