---
# System prepended metadata

title: Assignment 1 - Unity basics (ungraded)

---

# Assignment 1 - Unity basics (ungraded)

**Date**: 04/02/2023

**Group**: Group 17

**Group members participating**: Anna Górska, Răzvan Mazilu, Jędrzej Głowaczewski

**Activity duration**: 7 + watching tutorial

## Goal
To set up development environment, and learn basics of Unity.

## Plan
We follow the instructions in the exercises, read linked materials, and search for more information when necessary. Everyone follows exercise 3 almost independently, so that all of us get accustomed with Unity, and learn the basics. After we finish one sub-exercise we talk about the solution and one person commits the changes.

## Results

The Assignment is developed using the 2021.3.17f1 Unity editor version

### 3.1

#### 3.1.1, 3.1.2, 3.1.3
Create a new scene called Assignment 1, 
Add a 3D plane to your scene,
Add a 3D Cube to your scene.
![](https://i.imgur.com/vqVXcR8.png)

#### 3.1.4

Make the 3D Cube into a prefab and delete it from the scene.
![](https://i.imgur.com/ry8JTY9.png)


#### 3.1.5
Add an empty GameObject to your scene. Let's call it BasicBehavior.
![](https://i.imgur.com/7ZRw98d.png)

#### 3.1.6
Add a script to the BasicBehavior-GameObject. You can call it ObjectAdder
![](https://i.imgur.com/U40ATIb.png)


#### 3.1.7
Implement the script, such that when you click on Play; "Hello, World" will be printed in the Console.
![](https://i.imgur.com/uF6a1Nr.png)


#### 3.1.8
Extend the script, such that when you click on Play the 3D Cube-prefab is placed on the 3D plane.

![](https://i.imgur.com/D2FepMt.png)


#### 3.1.9
Fix your scene, such that 3D Cube is placed nicely on the 3D plane. 

This can be done by either altering the position of the prefab in script (changing the default (0,0,0) vector by altering the y-coordinates), or by modifying the prefab, so that the cube is a child of an empty GameObject.
Manually positioning of a prefab requires testing the right coordinates so that the plane is not cut through. In case of multiple prefabs with different shape and sizes, or any changes in shape and size, a better solution would be to use a parent object. When creating or editing the prefab it is enough to adjust the position of a child object in relation to the parent. This way prefab will sit nicely on top of a plane, and no changes in the code are required when the prefab changes.


![](https://i.imgur.com/7WEFmHh.png)


### 3.2
#### 3.2.1, 3.2.2 and 3.2.3
Adding material to the plane
![](https://i.imgur.com/5XGcQ0t.png)


### 3.3
#### 3.3.1
Adding Midair and Raycast prefabs
![](https://i.imgur.com/x7BS6XB.png)

#### 3.3.2
Instantiate Midair prefab in a fixed position when space button is pressed.
Instantiate Raycast prefab in a mouse position when left mouse button is pressed. 

```C#
void Update()
{
    if(Input.GetKeyDown(KeyCode.Space))
        Instantiate(midair, new Vector3(1, 3, 1), Quaternion.identity);
}
void FixedUpdate()
{
    if (Input.GetMouseButtonDown(0))
    {
        Ray ray = Camera.main.ScreenPointToRay(Input.mousePosition);
        RaycastHit hit;
        if (Physics.Raycast(ray, out hit))
            Instantiate(raycast, hit.point, Quaternion.identity);
    }
}
```
![](https://i.imgur.com/kj3R8pY.gif)


#### 3.3.3
##### Differences between Start() and Update():

The Start() method is run only once, when the script is activated. It can be used to initialize variables, setup the scene.

The Update() method is run once per frame. It can be therefore used for checking for input, moving and modifying objects during the play.

### 3.4

#### 3.4.1
##### How does Raycast work?
Raycast is a function thatis used to detect collisions with objects in a scene. It projects a ray into a scene, and it detects when the ray hit the object. It provides information on the collision, such as point and impact of hit. 


##### What happens whe collider has been removed from plane?

Since the collider has been removed from the plane, the raycast cannot detect a collision. Therefore the prefabs cannot be added on mouseclick.

#### 3.4.2
##### What happens when Rigidbody is added to the Prefab?
Adding rigidbody property to the prefab means that the prefab now has physical properties, such as mass, velocity, and friction. It can be used to simulate realistic physical behaviour, like being affected by forces, such as gravity.
![](https://i.imgur.com/lTmvwni.gif)
Here the objects fall freely due to gravity. No collidor on a plane means that they are not affected by the plane.

#### 3.4.3
##### What are the differences between different colliders, for example box and sphere?
With the prefab having box collider, and plane having box collider, the Midair objects collide with each other, and fall on a flat ground
![](https://i.imgur.com/Z99VrgY.gif)


With the plane having sphere collider, and prefab having box, the Midair objects no longer fall flat on the ground - the plane is now treated as a sphere
![](https://i.imgur.com/2JzvW3y.gif)


With the plane having box collider, and  Midair objects having sphere colliders, they roll on the ground instead of falling flat.
![](https://i.imgur.com/lzWQvaE.gif)


In summary, box collider defines a rectangular shape with flat sides, and sphere collider a spherical shape with curved terrain.


## Conclusion
We learned how to modify a scene, create and use assets, and how to control the scene with a script. We learned basics ideas of physics in Unity. Due to having trouble with understanding some concepts and implementing some features we decided to watch a Unity tutorial. This should help with being more conscious of performed exercises and being able to make deliberate choices when implementing new features. 

## References
https://docs.unity3d.com/Manual/index.html
