Advanced AI for Games; Behaviour Trees (Unity 6 Compatible) (Udemy.com)
Create your own Behaviour Tree API in C# and apply it in the Unity Game Engine
Created by: Penny de Byl
Last updated November 2024
What you will learn
- Students will learn the theory of behaviour tree design.
- Students will learn how to develop a behaviour tree API in C#
- Students will learn how to use behaviour trees to define the actions of non-player characters.
How it compares
Against the other 205 rated Udemy courses in Artificial Intelligence on CourseDuck:
- Rating4.6 out of 5higher than 79% of them
- Reviews362#119 of 206 by number of reviews
- Length7.3 hourslonger than 62% of them
- Last updatedNovember 2024earlier than 58% of them
Course Description
Behaviour Trees (BTs) are an A.I. architecture that provide game characters with the ability to select behaviours and carry them out, through a tree-like architecture that defines simple but powerful logic operations. It can be used across a wide range of game genres from first-person shooters to real-time strategies and developing intelligent characters capable of making smart decisions. The codebase is deceptively simple and yet logical, reusable and extremely powerful. The library is written in C# and implemented in Unity 2020, however will easily port to other applications.
The project has been tested in Unity 6!
In this course, Penny demystifies the advanced A.I. technique of BTs used for creating believable and intelligent game characters in games, using her internationally acclaimed teaching style and knowledge from almost 30 years working with games, graphics, and having written two award-winning books on games AI. Throughout, you will follow along with hands-on workshops designed to take you through every step of putting together your own BT API. You will build the entire BT library from the ground up, while building an art gallery simulation scenario in parallel, to test the API as you go.
Learn how to program and work with:
A Behaviour Tree Library and API that's reusable across a wide range of game projects.
Tree architectures, nodes, leaves, sequences, and selectors that define the behaviour of individual non-player characters (NPCs).
Navigation Meshes and Agents that provide advanced path planning and navigation capabilities for characters.
A Blackboard System that acts as a global inventory for world states and allows characters to communicate with each other.
Contents and Overview
Throughout the course, you will follow along while a BT library and API are constructed from the ground up, to allow you intimate knowledge of the codebase. Alongside this, a simple art gallery simulation will be constructed to test out the functionality of the library as it is put together. The simulation will also rely on Unity's NavMesh System for navigation and path planning.
The course begins with an overview of Behaviour Trees and covers all the fundamental elements (including trees, nodes, leaves, sequences, selectors, and other logical constructs). Code will be developed to navigate the Behaviour Tree and used to drive non-player characters in the art gallery including a robber, cop, visitors and workers. Throughout this, students will gain a solid knowledge of how Behaviour Trees are constructed and can be traversed, to apply actions to game characters.
At the completion of this course, students will have a fully-fledged BT library and API that they can reuse in their own game projects, to provide game characters with complex intelligent behaviours.
What students are saying about Penny's courses:
Turns out, the hardest part of this course for me is finding the words to describe how glad I am to have enrolled in it.
I honestly love Hollistic's teaching approach and I've never learned so much within a few hours about coding effectively with such detailed explanations!
Penny is an excellent instructor and she does a great job of breaking down complex concepts into smaller, easy-to-understand topics.
Instructor Details
- 4.6 Rating
362 Reviews
Penny de Byl
Hi, I'm Dr Penny de Byl. I'm a full stack developer of most things computer sciency and academic with a true passion for teaching. I've been teaching others about games development, programming, computer graphics, animation and web design for over 25 years in universities in Australia and Europe at the full professor level. I've also consulted for Unity, SAE, the Australian Institute of Entertainment and Wikitude. My best selling textbooks including Holistic Game Development with Unity are used in over 100 institutions world-wide. My graduates work at companies like Apple, Ubisoft, LinkedIn and Deloitte Digital.
I have an honours degree in computer graphics and a Ph.D. in artificial intelligence for games characters. Over the course of my career I've won numerous awards for teaching excellence at the state, national and international levels including the Australian Learning and Teaching Council's Excellence in Teaching Award and the Unity Mobile Game Curriculum Competition. My approach to teaching computer science and related fields is project-based giving you hands-on workshops you can immediately get your teeth into.
I want you to leave my virtual classroom fully armed with a toolkit of skills for life-long learning. I'm excited to now be focussing my efforts full-time on Udemy to bring my years of knowledge and experience to those eager to learn about technology.
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Reviews
By Zvi Katz on 7/16/2026
This course teaches a very important tool for designing and implementing character behavior in games. Behaviour Trees are essential for creating intelligent, dynamic, and responsive game characters, and this course explains them clearly and effectively. It also demonstrates everything through actual implementation in Unity using C#, which makes the concepts practical and easy to apply.
By Rob Michael on 12/14/2025
Another great course from Penny. As an Unreal AI programmer, I use behavior trees and blackboards every day, but I wanted to expand that knowledge to how to do them in Unity. With this course I now have a solid knowledge of how to create BTs & BBs, even though they're not built-in to the AI code of the engine, as they are with Unreal. I look forward to expanding my exploration & development of more advanced AI techniques in Unity, perhaps even exporting concepts from Unreal to Unity to make my AI behaviors even better.
By Kankles on 9/17/2023
Excellent course. The course is great if you're looking for a course to explain and implement the core elements of a behavior tree. I like course like this one, because it give me a tool that I can use in future projects. This course was exactly what I was looking for and I look forward to taking the GOAP course in the future. Only reason I didn't give it 5 stars is because I posted a question 3 days ago and still haven't received a response. Not a big deal though, as the course was taught well and I figured out a working solution.
By Octavio Ortega Novoa on 9/3/2023
Penny does a great job at teaching the base Behaviour Tree concepts, plus the implementations are really fun and interesting! Unfortunately I feel like its missing quite a lot in the quality of the API & the code in general, there's a lot of power in this to make a way more reusable system, for example using Scriptable Objects and maybe an editor window for easy design and debugging. Otherwise, it is a really good course!
By J B on 1/30/2023
Fantastic course. I'm very appreciative of Penny for covering intermediate topics like behaviour trees to this extent. The code could be cleaner and a git repo or something more than the occasional script/project snapshot would have been nice but it doesn't detract significantly from the course. I particularly enjoyed the fact that the course doesn't just introduce you to behaviour trees, implement them and then leave you to figure out the practicalities yourself. It actually spends a good amount of time over the last few sections manipulating and debugging the behaviour trees so you leave the course with what feels like practical experience and not just theoretical knowledge.
By Randolph Andrews on 6/4/2022
I thought the word Advanced in the course title actually meant it. I have looked and many behavior trees and have seen multiple techniques used. Some use injection while some use only events. Better behavior trees include some methods for sending or at least responding to events. I was also disappointed because there was no graphical editor. The patrons bunching up at the door to the gallery is something I would never want to have happen in a game.
By Joshuah Kusnerz on 5/16/2022
This is one of the best courses on behavior trees you can find. You not only build your own BT but you get fantastic explanations of the "whys" behind the functionality. This makes using and understanding premade BT assets like Behavior Designer a simple thing. After this course you will have an easy time adding BT to your own AIs.
By Ozan Can ACAR on 2/27/2022
This course is awesome! Dr. Penny is the only one who lectures about game AI techniques such as BTs and GOAP. I've completed both now. I've been using Unreal Engine in my workplace over a year but i'm using Unity since 2010. The Behavior Trees in Unreal are great so, if you'd like to carry your experience to Unity and create your own library I highly recommend this course. One request for Dr. Penny, please use different sound when you edit out something. The one you use scared the hell out of me :D.
By Julian Jacobson on 12/9/2021
I picked up this course to learn the basic building blocks that make up a BT. They cover how to set up a BT as well as the steps to create your own logic and types of leaf nodes. I like how if there is a problem with our code they explain as to WHY its happening and provide a great fix. There are also times where they provide insight on how to solve problems in the future on our BT/ Nodes as well as create our own custom Decorators and Composites. There are some issues though Overall 4/5. Would have been awesome if they showed us how to use a visual editor/visual scripting for our BT but honestly the way its set up you can easily live without one as long as you keep each parent node/children organized. I should mention there is a lot of going back and removing code, various video cuts where penny quickly changes code and it can be hard to follow. Even as someone who rarely has issues following tutorials it can become a bit scattered, though i understand there was a lot to cover . Also as of now the Resources folder with the fallback is BROKEN. I actually had to re-start the tutorial completely because my code was broken, I downloaded the Fallback Behavior Folder to replace my project and it was even worse! So RIP 4 and 1/2 hours of time. I think with bit more organization this would have been a definite 5/5 or even 6/5. Overall it was a good tutorial series and I plan on purchasing more material from Penny.
By Miguel Yee on 10/25/2021
Amazing course on behaviour trees, Penny gives a very detailed explanation on the structure, a potential library, and excellent challenges to learn. As someone that has taken many "intermediate" level courses I must warn people, most of them truly aren't, this stays true to that, it is not for beginners by any means, you should be comfortable with coding while taking the course or you'll have a very hard time with it since a lot of the concepts, outside Behaviour Trees, won't be explained.
Quality Score
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Overall Score : 92 / 100












