Extruded boss/base in Solidworks - Step-by-Step Guide

Introduction

Extruded boss/base lets you create a 3D shape by stretching a 2D sketch straight out. It helps you build solid parts from flat drawings quickly and easily.

When you want to turn a flat circle sketch into a cylinder shape.

When you need to add thickness to a flat rectangle to make a box.

When creating simple parts like rods, plates, or blocks from sketches.

When you want to build the main body of a part before adding details.

When you need to quickly make a solid shape from a profile for analysis or assembly.

Steps

Step 1: Click

- Features tab

Features toolbar appears with extrusion options

Step 2: Select

- Extruded Boss/Base button

Extrude property manager opens on the right side

Step 3: Choose

- Sketch on a plane or face

Sketch profile highlights for extrusion

Step 4: Enter

- Depth box in property manager

Preview of the 3D extrusion appears with specified length

💡 Use the arrow handle on the preview to adjust depth visually

Step 5: Click

- OK (green checkmark) button

Sketch is extruded into a solid 3D shape

Before vs After

Before

A flat 2D rectangle sketch on the front plane with dimensions 100mm by 50mm

After

A solid 3D rectangular block 100mm long, 50mm wide, and 20mm thick created by extrusion

Settings Reference

Direction 1

📍 Extrude property manager

Controls how far and in what way the sketch is extruded

Default: Blind

Draft

📍 Extrude property manager

Adds a taper angle to the extrusion sides for draft

Default: None

Thin Feature

📍 Extrude property manager

Creates a thin-walled extrusion instead of a solid block

Default: Disabled

Common Mistakes

Trying to extrude without a closed sketch profile

Extrusion requires a fully closed shape to create a solid

Ensure the sketch lines connect fully with no gaps before extruding

Setting extrusion depth too small or zero

No visible 3D shape will be created if depth is zero or too small

Enter a positive depth value that matches the desired thickness

Summary

Extruded boss/base creates 3D solids by stretching 2D sketches.

You must use a closed sketch and specify extrusion depth.

Settings like direction and draft control the extrusion shape.

Practice

1. What does the Extruded Boss/Base feature do in SolidWorks?

easy

A. It turns a 2D sketch into a 3D solid by stretching it.

B. It creates a hole through a 3D part.

C. It colors the surface of a 3D model.

D. It flattens a 3D model into 2D.

Solution

1. Step 1: Understand the purpose of Extruded Boss/Base

   This feature takes a flat 2D sketch and extends it into the third dimension to create a solid shape.

2. Step 2: Compare options with the feature's function

   Only It turns a 2D sketch into a 3D solid by stretching it. describes turning a 2D sketch into a 3D solid by stretching, which matches the feature's purpose.

3. Final Answer:

   It turns a 2D sketch into a 3D solid by stretching it. -> Option A

4. Quick Check:

   Extruded Boss/Base = 2D to 3D solid [OK]

Hint: Extruded Boss/Base = stretch 2D sketch into 3D solid [OK]

Common Mistakes:

• Confusing extrusion with cutting or coloring
• Thinking it flattens 3D to 2D
• Assuming it creates holes

2. Which of the following is the correct syntax to start an Extruded Boss/Base in SolidWorks?

easy

A. Select a 3D solid and click 'Extruded Boss/Base' to flatten it.

B. Draw an open line and click 'Extruded Boss/Base' without selecting a sketch.

C. Click 'Extruded Boss/Base' first, then draw the sketch on the 3D model.

D. Select a closed 2D sketch, then click 'Extruded Boss/Base' and set the depth.

Solution

1. Step 1: Identify the correct workflow for Extruded Boss/Base

   You must first have a closed 2D sketch selected before applying the extrusion feature.

2. Step 2: Evaluate each option's correctness

   Select a closed 2D sketch, then click 'Extruded Boss/Base' and set the depth. correctly describes selecting a closed sketch and then applying the feature with a depth. Other options describe incorrect sequences or actions.

3. Final Answer:

   Select a closed 2D sketch, then click 'Extruded Boss/Base' and set the depth. -> Option D

4. Quick Check:

   Closed sketch + Extruded Boss/Base = correct syntax [OK]

Hint: Always select closed sketch before extrusion [OK]

Common Mistakes:

• Trying to extrude open sketches
• Starting extrusion before sketching
• Selecting 3D solids instead of sketches

3. Given a square sketch of 50mm side length, what will be the volume of the solid after applying an Extruded Boss/Base with a depth of 20mm?

medium

A. 1000 cubic mm

B. 50000 cubic mm

C. 2000 cubic mm

D. 500 cubic mm

Solution

1. Step 1: Calculate the area of the square sketch

   Area = side x side = 50mm x 50mm = 2500 mm².

2. Step 2: Calculate the volume by multiplying area by extrusion depth

   Volume = area x depth = 2500 mm² x 20 mm = 50000 cubic mm.

3. Final Answer:

   50000 cubic mm -> Option B

4. Quick Check:

   Volume = 50x50x20 = 50000 [OK]

Hint: Volume = sketch area x extrusion depth [OK]

Common Mistakes:

• Multiplying side length by depth only
• Using wrong units or forgetting to square
• Confusing area with volume

4. You tried to create an Extruded Boss/Base but got an error saying the sketch is not closed. What is the most likely cause?

medium

A. The sketch is fully defined.

B. The extrusion depth is set to zero.

C. The sketch contains gaps or open endpoints.

D. You selected a 3D solid instead of a sketch.

Solution

1. Step 1: Understand the error message about sketch closure

   Extruded Boss/Base requires a closed sketch; gaps or open endpoints cause errors.

2. Step 2: Analyze options for the cause

   The sketch contains gaps or open endpoints. correctly identifies open sketch geometry as the cause. Other options do not relate to the 'not closed' error.

3. Final Answer:

   The sketch contains gaps or open endpoints. -> Option C

4. Quick Check:

   Open sketch = extrusion error [OK]

Hint: Check sketch for gaps before extrusion [OK]

Common Mistakes:

• Ignoring open endpoints in sketches
• Assuming zero depth causes closure error
• Confusing sketch selection with extrusion depth

5. You have a circular sketch with radius 10mm. You want to create a hollow cylinder by extruding the circle and then cutting a smaller concentric circle of radius 7mm through the entire depth. Which sequence of features should you use?

hard

A. Extruded Boss/Base with outer circle, then Extruded Cut with inner circle through all.

B. Extruded Cut first, then Extruded Boss/Base on the same sketch.

C. Use only Extruded Boss/Base with both circles selected.

D. Create two separate Extruded Boss/Base features for each circle.

Solution

1. Step 1: Create the solid cylinder by extruding the outer circle

   Use Extruded Boss/Base on the larger circle to form the solid cylinder.

2. Step 2: Remove the inner material by cutting the smaller circle

   Use Extruded Cut on the smaller circle sketch to hollow out the cylinder through the entire depth.

3. Final Answer:

   Extruded Boss/Base with outer circle, then Extruded Cut with inner circle through all. -> Option A

4. Quick Check:

   Boss then Cut = hollow cylinder [OK]

Hint: Extrude solid first, then cut inner shape [OK]

Common Mistakes:

• Trying to cut before creating the solid
• Selecting both circles for one extrusion
• Creating two solids instead of hollow