3D block with hole in center drawn using Onshape

Learning 3D CAD – The First Step

Learning the fundamentals of CAD will prepare you for the future of digital design and manufacturing. Designing in 3 dimensions allows you to quickly turn your ideas into reality. This guide will help you create your first 3D model.  Follow the instructions below to create your first 3D model and learn the fundamentals of CAD design.

The First Build:

Please complete the student info survey before starting the design.

Student Info Survey – Complete this first

The block and hole looks deceivingly simple yet takes a specific set of steps.  Every new designer should start with this first model since it showcases the “Theory of CAD”


3D block with hole in center drawn using Onshape

Theory of CAD:

Creating a 3D object uses one simple principal.

“Draw in 2 dimensions and stretch into the 3rd dimension”

Follow the instructions below to create your first 3D object using this principal.

Creating a Block

Follow these instructions carefully to create a 3D block in OnShape.  Onshape is a 3D design package that is free for students and educators.  It is great for students and classroom since it is web-based and doesn’t required you to install any software. Log into your OnShape account or create an account if you don’t have one.

Onshape 3D CAD

1) Creating a New Document:

  • Log into Onshape
  • Select “Create” and select “Document”
  • Name your Document “Block and Hole”

Create new CAD document in OnShape

2) The principal planes:

The first thing you will see on your screen are the 3 principal planes.  The Front, Top, and Right

3D CAD principal planes in OnShape

  • Hold the right mouse button and spin them around
  • Can you spin them in an interesting way?
  • Select a plane and hit the “N” key:   What happens?

3) Creating a Sketch

Sketches are used to draw in 2 dimensions.

  • Select the Front Principal plane and rotate the view to be perpendicular, also called “Normal”  (Short Cut: N)
  • Tip* Be sure to only select one plane. If you have multiple items selected you can use “Space bar” to clear selections
  • Use the “Sketch” button to create a new sketch (Short Cut: Shift+S)

Your screen should look like this to indicate you are in “Sketch Mode”

Indicators you are in a sketch


4) Drawing a Rectangle

There are multiple sketching tools available to draw in 2 dimensions.  We will start by drawing a rectangle.

  • Select “Center Point Rectangle”

Types of Rectangles in OnShape

  • Left click the center and draw outwards to draw the rectangle

Rectangle drawn in CAD

5) Adding Dimensions

Dimensions allow you to control the sizes of sketch entities.

  • Select the dimension button in tool bar (Shortcut: D)
  • Select one of the lines and drag the cursor
  • Set the value to 1 inch
  • Select the other line and set length to 1 inch

Adding dimensions to a rectangle in CAD


6) Making it 3D

Creating a 3D object in CAD uses one simple rule.  Draw in two dimensions and stretch into the 3rd dimension.  The 2 dimensional drawing is done and now it is time to stretch, also called “Extrude” into the 3rd dimension.  This is where the fun part is.

  • Select the extrude iconOnshape Extrude Icon
  • Ensure Sketch 1 is selected in the blue region or select Sketch 1 if it is blank
  • Change the depth to 3 inches

Extrude dialog box instructions

  • Hit the “Green Check” to create your part

Your part should look like this. Rotate your creation to inspect.  Show a friend and share something you learned.

3D block in OnShape

7) Cut a Circle

Creating the hole will be similar to making the block.  Instead of adding material we will cut material away.

  • Select the 1 inch face of the block

Selecting a Face in CAD Onshape

Tip* If you have more than one thing highlighted, you can hit space bar to clear selections or click anywhere on the screen

  • Change the view to be normal (Short Cut: N)


  • Create a new sketch (Short Cut: Shift + S)


  • Draw a circle in the center of the square


  • Dimension the circle to be 0.5 inches (Short Cut: D)

Circle with 0.5 dimension in CAD

  • Select the extrude icon


  • Select “Remove” to cut material instead of add


  • Select “Through all” to cut all the way through the part

Cut extrude dialog box Onshape CAD


  • Hit the green check to cut the hole


8) Continue your learning

3D block with hole in center drawn using Onshape

Congratulations on your first part.  The files can be downloaded and sent to a 3D printer if you wanted.  Now it is time to practice and create a 3D work of art.

  • Add at least one additional extrusions (or more!)


  • Add a least one additional hole (it could be a rectangular hole)

What can you make?

3D rectangular sculpture

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