Unlock the Power of Unreal Engine AI Teamwork

Table of Contents

1. Introduction
2. The Problem with NPC Characters
3. Implementing Team-Like Behavior
4. Creating NPC Managers
5. Assigning NPC Managers to NPC Characters
6. Making NPC Characters Search Locations
7. Checking if a Location Should be Searched
8. Handling Minor Threats
9. Implementing the Behavior Tree
10. Using the "Can I Search?" Decorator
11. Conclusion

Introduction

In this article, we will explore the concept of making NPC (non-player character) characters work as a team. Typically, when a disturbance occurs, such as a noise or a thrown object, all NPC characters will go to investigate the location. However, we want to implement a more intelligent behavior where only one NPC character will go to search the location, while the others remain at their original positions. By creating a shared consciousness among NPC characters and implementing NPC managers, we can achieve this team-like behavior. Let's dive into the details and learn how to make this happen.🧠💥

The Problem with NPC Characters

Currently, in many Game scenarios, when a disturbance occurs, all NPC characters respond by going to the location to explore what the noise is. While this approach works fine when there are only a few enemies, it becomes problematic when there are a large number of enemies. Having all enemies converge to the same location can cause overcrowding and make the behavior look unrealistic. Therefore, we need to find a way to make the NPC characters work more intelligently as a team.🚶‍♂️🚶‍♂️🚶‍♂️

Implementing Team-Like Behavior

To make NPC characters work as a team, we need to create shared consciousness among them. This means that each team of enemies, or factions, should share knowledge and make collective decisions. To achieve this, we will implement NPC managers as actor classes. These NPC managers will hold information and provide input to the NPC characters. By assigning NPC managers to NPC characters, we can establish a sense of team and enable them to make decisions based on shared knowledge.👥🧠

Creating NPC Managers

To begin, we will create an actor class called "NPC Manager" in the BP (blueprint) folder. The reason we implement this as an actor class is that we need to be able to place NPC managers in different levels and easily assign them to NPC characters. Within the NPC Manager class, we will add a variable called "Team ID" to identify which team the manager belongs to. This variable will be an integer and will default to zero. Additionally, we will need to create a reference to the NPC Manager in NPC characters so that they can access the manager's input and decisions. This can be done by adding a variable of type "NPC Manager" in the NPC character blueprint.👥🔧

Assigning NPC Managers to NPC Characters

Once we have created NPC Managers in the levels, we can assign them to NPC characters. To do this, select the NPC characters and assign the NPC Manager reference to them. If a valid NPC Manager reference already exists for an NPC character, there is no need to assign it again. However, if the NPC character does not have a valid reference, we can use the "Find Actors" function to search for the NPC Manager in the level and assign it to the NPC character. By doing this, we ensure that each NPC character has access to the Relevant NPC Manager for decision-making.🚶‍♂️🔧🧩

Making NPC Characters Search Locations

Now that we have established the connection between NPC characters and NPC Managers, we can implement the behavior of searching locations. When a disturbance occurs, such as a thrown rock or a noise, only one NPC character should go and check the location. To achieve this, we will add a function called "Can I Search?" in the NPC Manager blueprint. This function will determine whether an NPC character has permission to search a given location. If someone else is already searching that location or if it has been recently searched, the character should not search again. Only when it is necessary should a character be allowed to search a location. By implementing this logic, we can ensure that NPC characters behave intelligently as a team.🔍👥💪

Checking if a Location Should be Searched

To check whether a location should be searched, we need to compare the search location with the last search location. If the distance between the two locations is too close, there is no need to search again. However, if the distance is significant or it is a different location altogether, we should proceed with the search. Additionally, we need to factor in the time elapsed since the last search. If the time gap is too short, we should not search again. By considering both the location and the time, we can make informed decisions about whether a search is necessary.💡🔎⌛️

Handling Minor Threats

In the context of NPC behavior, minor threats refer to disturbances like footstep sounds or thrown objects that do not pose a significant danger. To handle minor threats, we will add a sub-behavior tree called "Search Minor Threat" in the main behavior tree. This sub-behavior tree will make the NPC character look at the direction of the disturbance, wait for a few seconds, and then move to the location. Before moving, we will use the "Can I Search?" decorator to check if the NPC character has permission to search the location based on the shared consciousness provided by the NPC Manager. By handling minor threats in this way, we can ensure that NPC characters respond appropriately without overcrowding the location.🚶‍♂️🔍🙌

Implementing the Behavior Tree

The behavior tree is responsible for dictating the actions and decision-making of NPC characters. In our case, we will use the behavior tree to search for minor threats and determine if a location should be searched. To do this, we will add a decorator called "Can I Search?" to the behavior tree. This decorator will check with the NPC Manager whether the NPC character has permission to search a given location. If granted permission, the character will execute the search behavior. Otherwise, the character will skip the search and continue with other actions. By using this decorator, we can ensure that NPC characters work as a team and avoid unnecessary duplicate searches.💪🌳🔍

Using the "Can I Search?" Decorator

To utilize the "Can I Search?" decorator in the behavior tree, we need to get a reference to the controlled pawn. From this controlled pawn, we can access the NPC Manager through the NPC interface. By implementing the "Can I Search?" function in the NPC Manager and calling it from the behavior tree, we can obtain whether the NPC character has permission to search a location. By connecting this decorator to relevant actions in the behavior tree, we can control the flow of searching and ensure that only one NPC character is assigned to search a specific location.✨🌳🚶‍♂️

Conclusion

In this article, we have explored how to make NPC characters work as a team by implementing shared consciousness and NPC Managers. By assigning NPC Managers to NPC characters and using the "Can I Search?" decorator, we can enable intelligent decision-making and prevent overcrowding of locations. This team-like behavior adds realism and depth to NPC character interactions, enhancing the overall gaming experience. Remember, this is just one approach, and there are endless possibilities for further enhancements and improvements. Let your creativity guide you as you continue to refine and perfect this system in your game development projects. Happy coding!🧠🌟🚀

Highlights

• Making NPC characters work as a team by implementing shared consciousness
• Preventing overcrowding of locations during disturbances
• Assigning NPC Managers to NPC characters for decision-making
• Implementing the "Can I Search?" decorator to control search behavior
• Enhancing the realism and depth of NPC character interactions
• Continuous improvement and enhancement possibilities✨👥🔧

Frequently Asked Questions (FAQ)

Q: Can multiple NPC Managers be assigned to the same NPC character? A: No, an NPC character can only have one assigned NPC Manager. This ensures that the NPC character is part of a specific team and follows team-based decision-making.

Q: What happens if an NPC character does not have a valid NPC Manager assigned? A: If an NPC character does not have a valid NPC Manager assigned, it means that the character operates independently and does not have access to shared consciousness. In this case, the character will always search the location.

Q: How can I handle major threats that require all NPC characters to respond? A: This system is designed for handling minor threats where only one NPC character needs to investigate. For major threats, you may need to implement a different approach, possibly involving a separate behavior tree or group behavior logic.

Q: Can NPC Managers have different teams or factions? A: Yes, NPC Managers can be assigned to different teams or factions by setting the "Team ID" variable. Each team or faction will have its own shared consciousness and decision-making.

Q: Is there a limit to the number of NPC characters that can be assigned to an NPC Manager? A: There is no hard limit to the number of NPC characters that can be assigned to an NPC Manager. However, keep in mind that assigning too many NPC characters to a single NPC Manager may impact performance, so it is advisable to optimize and test accordingly.🧐💡

Resources:

• Patreon page for project files
• Official documentation on NPC behavior