Unity 3D Developer Interview Questions And Answers

The inspector is a context-sensitive panel, where you can adjust the position, scale and rotation of Game Objects listed in Hierarchy panel.

A Unity3D files are scene web player files created by Unity; an application used to develop 3D games. These files consist of all assets and other game data in a single archive, and are used to enable gameplay within a browser that has the Unity Web Player Plugin. The assets within a 3D unity file are saved in a proprietary closed format.

To hide gameobject in Unity 3D, you have to use the code

gameObject.transform.SetActive(false);

The total number of sessions by all people playing on a given day. Also known as Total Sessions.

Prefab in Unity 3D is referred for pre-fabricated object template (Class combining objects and scripts). At design time, a prefab can be dragged from project window into the scene window and added the scene's hierarchy of game objects. If desired the object then can be edited.

At the run time, a script can cause a new object instance to be created at a given location or with a given transform set of properties.

Characteristics of Unity is:

It is a multi-platform game engine with features like ( 3D objects, physics, animation, scripting, lighting etc.)

► Accompanying script editor
► MonoDevelop (win/mac)
► It can also use Visual Studio (Windows)
► 3D terrain editor
► 3D object animation manager
► GUI System
► Many platforms executable exporter Web player/ Android/Native application/Wii
In Unity 3D, you can assemble art and assets into scenes and environments like adding special effects, physics and animation, lighting, etc.

During rendering, each pixel is calculated whether it should be illuminated and receive lightning influence, and this is repeated for each light. After approximately eight repeated calculations for different lights in the scene, the overhead becomes significant.

For large scenes, the number of pixels rendered is usually bigger than the number of pixels in the screen itself.

Deferred Lighting makes the scene render all pixels without illumination (which is fast), and with extra information (at a cost of low overhead), it calculates the illumination step only for the pixels of the screen buffer (which is less than all pixels processed for each element). This technique allow much more light instances in the project.

AssetBundles are files that can be exported from Unity to contain asset of your choice. AssetBundles are created to simply downloading content to your application.

The percentage of monthly active users who play on a given day. Also known as Sticky Factor in the analytics and game industries, this metric is often used as one estimate of player engagement.

Note that the metric includes both returning and new players. An influx of new players could mask the exit (churn) of existing players. In other words, a steady DAU per MAU metric doesn’t mean high player engagement if players are leaving your game just as fast as they join. Always examine retention metrics as well.

Average verified IAP revenue per user who completed a verified IAP transaction.

The most important thing here is to answer relatively quickly, and back it up. One of the fallouts of this question is age. Answering "Robotron!" to a 20-something interviewer might lead to a feeling of disconnect. But sometimes that can be good. It means you have to really explain why it's the best game of all time. Can you verbally and accurately describe a game to another person who has never played it? You'll rack up some communication points if you can.

What you shouldn't say is whatever the latest hot game is, or blatantly pick one that the company made (unless it's true and your enthusiasm is bubbling over). Be honest. Don't be too eccentric and niche, and be ready to defend your decision.

At smaller studios, this is the 64 million dollar question. My advice is to be 100 percent honest. If you won't crunch, say so now. It may well put you out of the running for a job, but ultimately that's a good thing. No, really, it is! If the company works a lot of overtime and you don't want to do it, then taking the job is going to be punishing for everyone.

Having said that, the last thing any interviewer wants to hear is, "I won't do it" because that predicates a perceived lack of involvement and passion (not that passion should equal overtime, but the perception of refusing to do something before you're even in the circumstances could be the difference between getting a job offer and having the company pass you up).

☛ Awake()
☛ OnEnable()
☛ Start()
☛ Update()
☛ LateUpdate()
☛ OnGUI()
☛ OnApplicationQuit()
☛ OnDisable()
☛ OnDestroy()

Note: You might be tempted to disagree with the placement of OnApplicationQuit() in the above list, but it is correct which can be verified by logging the order in which call occurs when your application closes.

The issue is that you can't modify the position from a transform directly. This is because the position is actually a property (not a field). Therefore, when a getter is called, it invokes a method which returns a Vector3 copy which it places into the stack.

So basically what you are doing in the code above is assigning a member of the struct a value that is in the stack and that is later removed.

Instead, the proper solution is to replace the whole property; e.g.:

using UnityEngine;
using System.Collections;
public class TEST : MonoBehaviour {
void Start () {
Vector3 newPos = new Vector3(10, transform.position.y, transform.position.z);
transform.position = newPos;
}
}

☛ What is Coroutine,is it running on new thread?
☛ Difference between Stack and Heap.
☛ What do you mean by Inheritance ? Explain with example.
☛ What do you mean by Polymorohism? Explain with example.
☛ What is overriding ?
☛ What is overloading ?
☛ Difference between overriding and overloading.
☛ What is the use of Virtual keyword ?
☛ Difference between Static Class and Singleton.
☛ What is Abstract Class ?
☛ Difference between Abstract Class and interface.
☛ What is Serialization and De-Serialization ?
☛ Does C# support multiple inheritance ?
☛ What do you mean by Generic Function or Generic Class ?

☛ Difference between Update,Fixed Update and Late Update.
☛ What is Prefabs in Unity 3D?
☛ What is the use of AssetBundle in Unity?
☛ What is difference between Resources and StreamingAssets Folder.
☛ What is Batching and what is the use of Batching?
☛ Difference between Destroy and DestroyImmediate unity function
☛ Difference between Start and Awake Unity Events
☛ What is the use of deltatime?
☛ Is this possible to collide two mesh collider,if yes then How?
☛ Difference between Static and Dynamic Batching.
☛ What is the use of Occlusion Culling?
☛ How can you call C# from Javascript, and vice versa?

☛ What is the best game that you made with Unity?
☛ Which app on the app store did you make most money from?
☛ How did you create asset bundles for your game?
☛ What do you think about the threading model in Unity?
☛ When would you use plugins?
☛ How can you call c# from Javascript, and vice versa?
☛ How active are you on the forum and answers sites? (What's your username?)
☛ What editor scripting have you done, and how did that go?
☛ What is one change/improvement you'd make to Unity?
☛ What source code revision software would you recommend using?

No. Collision events between two objects can only be raised when one of them has a RigidBody attached to it. This is a common error when implementing applications that use "physics."

The inspector panel allows users to modify numeric values (such as position, rotation and scale), drag and drop references of scene objects (like Prefabs, Materials and Game Objects), and others. Also it can show a custom-made UI, created by the user, by using Editor scripts.

The project panel contains files from the file system of the assets folder in the project's root folder. It shows all the available scripts, textures, materials and shaders available for use in the project.

The hierarchy panel shows the current scene structure, with its GameObjects and its children. It also helps users organize them by name and order relative to the GameObject's siblings. Order dependent features, such as UI, make use of this categorization.

The panel responsible for referencing content in the build process is the hierarchy panel. The panel contains references to the objects that exist, or will exist, when the application is executed. When building the project, Unity searches for them in the project panel, and adds them to the bundle.

class Mover : MonoBehaviour
{

Vector3 target;
float speed;

void Update()
{
float distance = Vector3.Distance(target,transform.position);
// will only move while the distance is bigger than 1.0 units
if(distance > 1.0f)
{
Vector3 dir = target - transform.position;
dir.Normalize(); // normalization is obligatory
transform.position += dir * speed * Time.deltaTime; // using deltaTime and speed is obligatory
}
}
}

Some important Unity 3D components include:

► Toolbar: It features several important manipulation tools for the scene and game windows.

► Scene View: It is a fully rendered 3 D preview of the currently open scene is displayed and enables you to add, edit and remove GameObjects

► Hierarchy: It displays a list of every GameObject within the current scene view

► Project Window: In complex games, project window searches for specific game assets as needed. It explores the assets directory for all textures, scripts, models and prefabs used within the project

► Game View: In unity you can view your game and at the same time make changes to your game while you are playing in real time.

Fixed Timestep feature helps to set the system updates at fixed time interval. A queue like mechanism will manage all real-time events that are accumulated between time epochs. If frame-rate drops below some threshold limit set for fixed timestep, then it can affect the game speed.

No. Texture and Meshes are examples of elements stored in GPU memory and Unity doesn't allow other threads, besides the main one, to make modifications on these kinds of data.

No. Fetching the Transform reference isn't thread safe in Unity.

When using threads, we must avoid using native Unity structures like the Mathf and Random classes:

class RandomGenerator : MonoBehaviour
{
public float[] randomList;
void Start()
{
randomList = new float[1000000];
Thread t = new Thread(delegate()
{
while(true)
{
Generate();
Thread.Sleep(16); // trigger the loop to run roughly every 60th of a second
}
});
t.Start();
}
void Generate()
{
System.Random rnd = new System.Random();
for(int i=0;i<randomList.Length;i++) randomList[i] = (float)rnd.NextDouble();
}
}

The number of different players who started a session on a given day. The Unity Analytics system anchors its days on Coordinated Universal Time (UTC), so the DAU figure counts players between 0:00 UTC and 24:00 UTC, no matter which timezone they are located in. A new session is counted when a player launches your game or brings a suspended game to the foreground after 30 minutes of inactivity.

DAU includes both new and returning players.

UE4:
► Game logic is written in C++ or blueprint editor
► Base scene object- Actor
► Input Events- Component UInputComponent of Actor class
► Main classes and function of UE4 includes int32,int24, Fstring, Ftransform, FQuat, FRotator, Actor and TArray
► To create a new instance of a specified class and to point towards the newly created Actor. UWorld::SpawnActor() may be used
► UI of Unreal Engine 4 is more flexible and less prone to crashes
► It does not support systems like X-box 360 or PS3, it requires AMD Radeon HD card to function properly
► Less expensive compare to Unity3D
► To use UE4 you don't need programming language knowledge

Unity3D:
► Game logic is written using the Mono environment
► Base scene object- GameObject
► Input events- Class Input
► Main classes and function include int,string,quaternion,transform, rotation, gameobject, Array
► To make a copy of an object you can use the function Instantiate()
► The asset store of this tool is much better stacked than UE4
► It supports wide range of gaming consoles like X-box and PS4, as well as their predecessors
► Unity3D has free version which lacks few functionality while pro version is bit expensive in compare to UE4
► It requires programming language knowledge.