Create a Basic Box Car in Unity 3D

In this lesson, you'll create a rudimentary vehicle that you can move around. You'll also create a basic obstacle course so that you can get some practise with the techniques you learned in the previous lesson: moving, scaling, and rotating. You'll also learn how to duplicate objects and how to group them. You'll also get a look at how to create a material so that you can add some colour to your game. And you'll finally get to do some programming. Off we go then!

 

Creating a Basic Box Car

We're going to be creating a rudimentary driving game in Unity. So, obviously we need a car. The car we'll build will be just a simple box car made out of cubes and cylinders. It will look something like this, when you're done:

A boxcar built with 3D objects in Unity

Pretty basic, hey! But it will give you some practise with the various toolbar icons, and grouping simple shapes.

You can either create a new project for this, or use the project you started in the previous section. To create a new project, click File > New Project from the menu at the top of Unity. Once you've clicked File > New Project, you'll see the Unity Hub dialog appear, the same one as last time. We'll use the project started in the previous section, though.

Locate the Project area at the bottom of Unity:

The Project area of Unity with a sample scene highlighted

By default, Unity names the scene you get with a new project Sample Scene. You can rename it, though. To do so, right click on Sample Scene. From the menu that appears, select Rename. The Sample Scene icon will turn blue, ready for you to type a new name. You can call it anything you like. But we've called ours Lesson Two:

The sample scene renamed

If you have a look at the Hierarchy on the left, you'll see that the top item is now also called LessonTwo:

The Hierarchy in Unity with the scene renamed

Now let's add a cube to the scene. (Or just keep the one you had from last time.)

If you haven't got a cube yet, from the menu at the top of Unity, click on the Game Object menu item. From the menu, select 3D Object > Cube.

The default name for your cube will be just Cube. If you added another, it would be Cube2, then Cube3, etc. But you can rename your game objects. You can rename your cube, either from the Hierarchy or the Inspector. In the Hierarchy, just right-click on Cube. From the menu that appears, select Rename. Then type a new name for it. Call it Car.

To rename using the Inspector, look at the top of the Inspector. You'll see it says Cube:

Inspector rename game object

This is a text box. So, click inside the text box. Delete the word Cube, then type Car instead. Press the enter key on your keyboard to complete the rename:

A game object renamed through the Inspector

Double-click on your Car cube to zoom in. (Or use your mouse wheel.)

We'll use this first cube as the main body of the car. So it needs to be elongated. Change the values for the Scale in the Transform area of the Inspector to these values:

X: 1
Y: 0.5
Z: 2

The Transform area should look like this:

Changing the scale of 3D cube

Now let's duplicate this cube.

In the Hierarchy window, make sure your car is selected. Right-click and select Duplicate from the menu:

Duplicate a game object via the Hierarchy

(A shortcut to duplicate game objects is to press the CTRL + D on your keyboard, when you have an object selected.)

You should now have an item called Car (1) in your Hierarchy:

A duplicated game object

With Car 1 selected change the following values in the Transform area of the Inspector:

Position

Y: 0.5
Z: -0.5

And change the Scale values to these:

X: 1
Y: 0.5
Z: 1

Your Transform area for Car 1 should look like this:

A cube rescaled

The Car in the Scene should look like this:

An arrangement of two cubes in Unity

Incidentally, if there's a Camera icon blocking your view, you can hide the Camera in Unity. You might see this:

The camera icon in Scene view

To hide the camera, locate the Gizmos panel at the top right of the scene:

The Gizmos icon in Unity

Click the white arrow to the right of Gizmos to reveal a dropdown box (the image below shows the area at the top):

A list of Gizmos

You can either adjust the slider to the left to make the camera smaller or uncheck the 3D Icons box. Adjusting the slider seems to give you better results.

Now let's add some wheels to our box car.

For the wheels, we can just add some cylinders.

From the menu at the top of Unity, click the Game Object item. From the Game Object menu, select 3D Object > Cylinder.

Now you need to move this cylinder into position. This means resizing, rotating and moving the cylinder. If you've stuck to the same measurements as in these tutorials, then set the following values for the cylinder's Transform in the Inspector:

Position

X: 0
Y: -0.1
Z: 0.7

Rotation

X: 90
Y: 0
Z: 90

Scale

X: 0.4
Y: 0.66
Z: 0.5

Here's what your Inspector should look like:

The Transform values of a cylinder

If your front wheels look all wrong, then use the techniques you've learnt so far to manoeuvre them into position. (The Move tool, the Rotate tool, and the Scale tool.)

To get a second set of wheels, duplicate the first set just like you did when you duplicated the cube. Now, in the Scene, use the blue arrow to move them to the back of the box car. (We moved ours to a Z Position of -0.7 instead of the 0.7 we used or the front wheels. The other values should be the same.)

But your box car should now look like this:

A basic boxcar using cubes and cylinders

Now let's add a surface for our box car to sit on.

 

Planes in Unity

A plane is another 3D game object you can add to your scene. These are usually used as a foundation you can build your scene on. They are quite easy to add.

From the menu at the top of Unity, click on the Game Object item. From the Game Object menu, select 3D Object > Plane:

Unity menu to add a Plane to a scene

When you click on Plane, you should see a thin white square appear under your car. You can make a plane as big as you want. They can be huge for things like RPG games. But we only need something small. So, with your Plane selected in the Hierarchy, change the Scale in the Transform area of the Inspector to 4 for the X, Y and Z values:

Changing the Scale of a plane

Your scene should look like this:

A boxcar sitting on a Plane

However, if you zoom in on your car (double-click it in the Hierarchy) you'll see that it's hovering above the plane. To fix this, you can either lower the car or raise the plane. We'll raise the plane.

With your plane selected in the Hierarchy, change the Y Position in the Transform area of the Inspector to -0.3. The X and Z can both be on zero, if they are not already.

Changing the Transform Y Position in the Inspector

(If your car is still not sitting on your plane, raise or lower it until it is.)

 

Grouping Game Objects in Unity

Let's rename a few of our game objects so we know what's what. In the Hierarchy, click on Car (1) to select it. This should be the top of your car. Using the techniques you learned earlier, rename this to CarTop. Click on Cylinder and rename this to WheelsFront. Now click on Cylinder (1) and rename this WheelsBack. Your Hierarchy should then look like this:

The Unity Hierarchy with a list of items

If you were to click on the Car object right now and tried to move it, it would just move the bottom of the car. The car top and the wheels would stay where they were. To solve that, you can group your objects.

So, in the Hierarchy, hold your left mouse button down on the CarTop object. Keep it held down and drag the CarTop object onto the Car object:

Drag and drop in the Hierarchy

When you let go of your left mouse button, the CarTop will become a child of the Car object. It will be indented, and Car will have an arrow beside it:

A grouped item in the Hierarchy

Now do the same for the wheels. Drag WheelsFront onto Car, then drag WheelsBack onto Car. When you're done, your hierarchy will look like this:

An example of object grouping the Hierarchy in Unity

(You can click the arrow to the left of Car to show or hide the objects under the Car item.

Car is known as the parent object. The three items under it are children of the Car object. If you move the Car, the child objects will move with it. When we come to move the car with code, we don't need to move every child and the car. We just need to move the parent object and the children will move with it.

Now let's add a bit of colour to our world.

 

Unity Materials

If you select the Plane object, then look at the Inspector, you'll notice that there's no direct way to change its colour. That's because things like colour changes are done through materials. The idea is, you create a material, apply a colour to that, and then apply the entire material to a game object or objects. Let's see how it works.

In the Project area at the bottom, click on the Assets folder. On the right of the folder list, in the bigger area, you'll see that the Assets folder contains another folder called Scenes. The scene you're working on is in this folder. It doesn't have to be, though. If you were really messy, you could just dump everything in the Assets folder without creating other folders to hold things like your scenes, your materials, and your scripts. We'll be nice and tidy, though. So let's create a folder for our materials.

Right-click on the Assets folder. You'll see a menu appear. From the menu, select Create > Folder:

The new folder menu in Unity

A new folder will be created inside the Assets folder. With the new folder highlighted, type a new name for it. Call it Materials. Your Project area will then look like this:

A Materials folder created in the Projects area of Unity

You can either double-click a folder name in the big area to move inside of it. Or left click in the small area on the left to move inside of a folder.

To create a material, either right-click when you're inside of the Materials folder, or right-click the folder name itself. From the menu that appears, select Create > Material:

Menu showing the Material item selected

When you create a material, you'll see an icon appear inside your folder. Type a new name for the material. Call it PlaneColor. The icon will then change to a grey sphere:

A Material renamed

Now look at the right-hand side of Unity. You'll see that the Inspector has lots of new items to choose from:

The Unity Inspector showing a Material

To add a colour to your material, the item you want is Albedo. But first, notice the sphere at the bottom. Now click the icon that looks like two semi-circles, one on top of the other:

Selected 3D shape icon

Clicking the icon will cycle you through all the various shapes that you can create with Unity. Stop when you get to the Plane:

A Plane selected

Now locate the Albedo item at the top of the Inspector:

The Albedo item highlighted in the Inspector

Click on the white square to bring up a color box:

A color wheel

Select a colour from the dialogue box. The plane is going to be our road, so we've went for a grey color. Notice the Hexadecimal box at the bottom. You can type a new colour in here. Our grey colour has a Hex value of A4A3A3:

A color wheel with a Hexidecimal value

To apply your colour to a game object, you can either drag the material onto the object in the scene, or drag it onto the game object in the Hierarchy:

A Material being applied to a Plane in a Unity Scene

Your plane will then be coloured:

The Scene with a Material applied

Now try these exercises.

Exercise
Using the techniques you've just learned, create a material for the car. Add a colour to your material and apply it to the car top and car body.

Exercise
Create a material for the car's wheels. Add a colour and apply it.

Exercise
Create some windows for your car. To do this, you can duplicate the top of the car, then resize and move them into place. Create a material for your windows and colour them.

When you've finished the exercises, your car might look something like this:

A boxcar made up of cubes and cylinders

Congratulations! You have now created your very own box car. All right, it looks like something Homer Simpson might design, but you did it all yourself. And you now have some very useful Unity skills. So, well done! By now, though, you're probably dying to get the damn thing to move. We'll do that next, as we tackle some coding.

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