Day 13
3D
90 XP

EXTRUDE

Push 2D shapes into 3D solids.

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Learning objective

By the end of this lesson you can push a closed 2D shape into a 3D solid using the EXTRUDE command.

What EXTRUDE is

EXTRUDE pushes a closed 2D profile (polyline, circle, region) along a height to create a 3D solid object.

Why and when you use it

EXTRUDE is the entry point into 3D modelling. Walls, prisms, cylinders, custom shapes — all start as a 2D profile that gets extruded.

Where to find it in the AutoCAD interface

Ribbon
3D Modeling workspace → Home tab → Modeling panel → Extrude.
Menu
Draw menu → Modeling → Extrude.
Command line
Type EXTRUDE and press Enter.
Alias / shortcut
EXT (then Enter).

Key vocabulary

Profile
The closed 2D shape that gets pushed into 3D.
Height / depth
How far the profile travels along the extrusion direction.
Solid
A 3D object with volume — supports boolean operations.
Workspace
Preset arrangement of ribbon panels. Switch to '3D Modeling' for solids tools.

Before you start

  • Switch workspace to '3D Modeling' (gear icon on the status bar).
  • Draw a closed polyline or circle — open shapes will extrude into surfaces, not solids.
  • Type VS, Enter, C, Enter to switch to Conceptual visual style so you can see solids.

Step-by-step instructions

  1. 1
    Switch to 3D Modeling workspace
  2. 2
    Draw a closed profile
  3. 3
    Start the EXTRUDE command
  4. 4
    Select the profile
  5. 5
    Type the height
  6. 6
    Switch visual style to Conceptual

Visual reference

Common mistakes & fixes

  • EXTRUDE produces a surface, not a solid.
    Fix: Your profile wasn't closed. JOIN the segments into a single closed polyline first.
  • Solid is invisible.
    Fix: You're still in 2D Wireframe visual style — switch to Conceptual (VS → C).
  • Solid extrudes the wrong way.
    Fix: Type a negative height, or rotate the view (ViewCube) before extruding.

Troubleshooting

AutoCAD says 'object is not closed'.Show
Cause: There's a gap in the polyline.
Fix: Run JOIN with OSNAP first, or use BOUNDARY to make a closed polyline from a hatchable region.
Solid looks flat from this angle.Show
Cause: You're looking down the extrusion axis.
Fix: Use the ViewCube to orbit to a 3/4 view.

Practice exercise

Hexagon → 100-unit tall prism
  1. Switch to 3D Modeling workspace.
  2. Type POLYGON, Enter, 6, Enter — draw a hexagon.
  3. Type EXT, Enter. Select the hexagon. Enter.
  4. Type 100 and Enter.
  5. Switch visual style to Conceptual.
Success looks like: A solid hexagonal prism, 100 units tall, shaded so you can see all three visible faces.

Pro tips & related commands

Pro tips
  • EXTRUDE has a Taper option — type T inside the command for an angled extrusion.
  • EXTRUDE has a Path option — type P to extrude along an existing line or polyline.
  • Use PRESSPULL as a quick alternative for face-based push/pull modelling.
Related commands
  • PRESSPULL
    Push or pull a face by clicking and dragging it.
  • REVOLVE(REV)
    Sweep a profile around an axis to make a solid of revolution.
  • UNION(UNI)
    Combine two solids into one.
Lesson quiz
0/2 correct

Score at least 2/2 to unlock lesson completion.

1. EXTRUDE only works on what kind of shape?
2. Which workspace lets you see 3D solids easily?

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JOINPOLYLINE Deep-Dive

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