EXTRUDE command for 3D from 2D in AutoCAD - Cheat Sheet & Quick Revision

Recall & Review

beginner

What does the EXTRUDE command do in AutoCAD?

The EXTRUDE command turns 2D shapes into 3D objects by stretching them along a straight path.

beginner

Which types of 2D objects can you extrude in AutoCAD?

You can extrude closed 2D shapes like circles, rectangles, and polygons to create 3D solids.

beginner

How do you specify the height of extrusion in AutoCAD?

After selecting the 2D object, you enter the height value or drag the mouse to set how far the shape is stretched upward.

intermediate

Can you extrude open 2D lines in AutoCAD?

No, open 2D lines cannot be extruded into solids. Only closed shapes can be extruded to form 3D solids.

intermediate

What is the difference between extruding a 2D shape and a 3D face in AutoCAD?

Extruding a 2D shape creates a 3D solid, while extruding a 3D face extends the surface but may not create a solid.

What is the first step to use the EXTRUDE command in AutoCAD?

A Enter the extrusion height

B Select a 2D closed shape

C Switch to 3D view

D Save the drawing

You must first select a 2D closed shape to extrude before specifying the height.

Which of these can NOT be extruded into a 3D solid?

A Open polyline

B Rectangle

C Polygon

D Circle

Open polylines are not closed shapes and cannot be extruded into solids.

How do you define the extrusion distance?

A By changing the line type

B By selecting a color

C By choosing a layer

D By typing a height value or dragging the mouse

The extrusion distance is set by entering a height or dragging the mouse after selecting the shape.

What happens if you extrude a 2D shape with zero height?

A A 3D solid is created

B The shape is deleted

C No 3D object is created

D The shape changes color

Extruding with zero height does not create a 3D object.

Which command is used to create 3D solids from 2D shapes in AutoCAD?

A EXTRUDE

B OFFSET

C TRIM

D FILLET

The EXTRUDE command creates 3D solids by stretching 2D shapes.

Explain how the EXTRUDE command transforms a 2D shape into a 3D object in AutoCAD.

Think about stretching a flat shape upward.

Describe the limitations of the EXTRUDE command regarding the types of 2D objects it can work with.

Consider what happens if the shape is not fully closed.

Practice

1. What does the EXTRUDE command do in AutoCAD?

easy

A. It colors 2D shapes with different shades.

B. It converts 3D objects back to 2D shapes.

C. It deletes 2D shapes from the drawing.

D. It turns 2D shapes into 3D objects by adding height.

Solution

1. Step 1: Understand the purpose of EXTRUDE

   The EXTRUDE command is used to add height or thickness to flat 2D shapes.

2. Step 2: Identify the effect on 2D shapes

   By stretching the 2D shape vertically, it becomes a 3D object.

3. Final Answer:

   It turns 2D shapes into 3D objects by adding height. -> Option D

4. Quick Check:

   EXTRUDE adds height to 2D shapes [OK]

Hint: EXTRUDE adds height to flat shapes to make 3D [OK]

Common Mistakes:

• Thinking EXTRUDE changes color
• Confusing EXTRUDE with deleting shapes
• Believing EXTRUDE flattens 3D objects

2. Which of the following is the correct syntax to start the EXTRUDE command in AutoCAD?

easy

A. Type EXTRUDE and press Enter

B. Type EXTRUDE3D and press Enter

C. Type EXTRUDE2D and press Enter

D. Type EXTRUDE_SHAPE and press Enter

Solution

1. Step 1: Recall the command name

   The correct command to extrude shapes in AutoCAD is EXTRUDE.

2. Step 2: Confirm the syntax to start the command

   Typing EXTRUDE and pressing Enter activates the command.

3. Final Answer:

   Type EXTRUDE and press Enter -> Option A

4. Quick Check:

   EXTRUDE command starts with 'EXTRUDE' [OK]

Hint: Start EXTRUDE by typing 'EXTRUDE' then Enter [OK]

Common Mistakes:

• Using incorrect command names like EXTRUDE3D
• Adding extra suffixes to the command
• Confusing with other 3D commands

3. Given a closed 2D circle with radius 5 units, what will be the height of the 3D cylinder after running EXTRUDE with a height value of 10 units?

medium

A. 10 units

B. 5 units

C. 15 units

D. 50 units

Solution

1. Step 1: Understand the input shape and extrusion height

   The 2D shape is a circle with radius 5 units. The extrusion height given is 10 units.

2. Step 2: Determine the resulting 3D object's height

   The EXTRUDE command adds the specified height (10 units) vertically to the shape, creating a cylinder of height 10 units.

3. Final Answer:

   10 units -> Option A

4. Quick Check:

   Extrusion height = 10 units [OK]

Hint: Extrusion height equals the input height value [OK]

Common Mistakes:

• Confusing radius with extrusion height
• Adding radius and height incorrectly
• Assuming extrusion multiplies dimensions

4. You tried to extrude a 2D open polyline but got an error. What is the most likely cause?

medium

A. You used the wrong command name.

B. The extrusion height was set to zero.

C. The polyline is not closed, so extrusion is not possible.

D. The 2D shape is already 3D.

Solution

1. Step 1: Understand extrusion requirements

   EXTRUDE requires closed 2D shapes to create 3D solids.

2. Step 2: Identify the problem with an open polyline

   An open polyline is not closed, so AutoCAD cannot extrude it into a solid.

3. Final Answer:

   The polyline is not closed, so extrusion is not possible. -> Option C

4. Quick Check:

   Closed shape needed for extrusion [OK]

Hint: Ensure shape is closed before extruding [OK]

Common Mistakes:

• Trying to extrude open shapes
• Ignoring extrusion height value
• Using wrong command names

5. You have a 2D rectangle with length 8 units and width 4 units. You want to create a 3D box with volume 192 cubic units using the EXTRUDE command. What extrusion height should you enter?

hard

A. 24 units

B. 6 units

C. 12 units

D. 48 units

Solution

1. Step 1: Calculate base area of the rectangle

   Area = length x width = 8 x 4 = 32 square units.

2. Step 2: Use volume formula to find extrusion height

   Volume = base area x height. So, height = Volume ÷ base area = 192 ÷ 32 = 6 units.

3. Final Answer:

   6 units -> Option B

4. Quick Check:

   Height = Volume / Area = 6 units [OK]

Hint: Divide volume by base area to get extrusion height [OK]

Common Mistakes:

• Multiplying instead of dividing for height
• Using length or width as height
• Ignoring units in calculation