Building a Complex Architecture System for Simulation Games in Unreal Engine

Building a Complex Architecture System for Simulation Games in Unreal Engine

Simulation games have become an essential genre in the gaming industry, with a specific focus on systems that allow for deep player interaction, creativity, and strategy. One such critical system is a building or architecture system, where players can create and modify structures in a simulated environment. This article will walk through how to build a complex architecture system for simulation games in Unreal Engine, covering all the necessary components and presenting code examples that can be directly applied to a game project.

Why is a Complex Architecture System Important?

A building system in a simulation game isn’t just about placing objects. It involves understanding how to manipulate the world with real-time interactions, handle structural integrity, simulate physics, and manage resources. The complexity arises in how these elements interact, ensuring that they are fun, intuitive, and stable in terms of gameplay.

A robust system adds depth to the game, allowing players to build elaborate structures with realistic physics and dynamic environmental effects. As a game developer, building a system that integrates multiple mechanics — such as collision, snapping objects, user interfaces for building, and more — is essential.

What is the Architecture System?

The architecture system in Unreal Engine for a simulation game involves:

1. Object Placement: Placing building blocks or modules in the world.
2. Snapping Mechanism: Ensuring blocks align properly in 3D space.
3. Physics Simulation: Handling the collision, weight, and gravity of placed objects.
4. Resource Management: Ensuring players need to gather resources for construction.
5. UI Integration: Providing a user-friendly interface for placing and interacting with structures.
6. Destruction and Damage System: Allowing players to destroy or modify structures in realistic ways.

Where Is It Used?

Such a building system is typically used in simulation games, such as:

• City Builders (e.g., SimCity or Cities: Skylines)
• Survival Games (e.g., Minecraft, ARK: Survival Evolved)
• Open-World Games (e.g., Rust, Fortnite)

Players often interact with such systems by constructing buildings, modifying the environment, and maintaining these structures against environmental factors or other players.

Example Code for a Complex Building System

Below, I will walk through the implementation of various components that make up a complex architecture system. We will cover the core parts and provide reusable code snippets for each functionality.

1. Object Placement and Snapping Mechanism

The most basic functionality of the system is placing objects in the world with proper alignment.

// BuildingBlock.h
#pragma once

#include "CoreMinimal.h"
#include "GameFramework/Actor.h"
#include "BuildingBlock.generated.h"

UCLASS()
class MYGAME_API ABuildingBlock : public AActor
{
	GENERATED_BODY()

public:
	// Sets default values for this actor's properties
	ABuildingBlock();

protected:
	// Called when the game starts or when spawned
	virtual void BeginPlay() override;

public:
	// Called every frame
	virtual void Tick(float DeltaTime) override;

	// The mesh of the building block
	UPROPERTY(VisibleAnywhere)
	UStaticMeshComponent* BlockMesh;

	// Function to snap the block to the grid
	void SnapToGrid(FVector GridLocation);

	// Function to handle placement of the block
	void PlaceBlock(FVector Location);
};

// BuildingBlock.cpp
#include "BuildingBlock.h"

// Sets default values
ABuildingBlock::ABuildingBlock()
{
	PrimaryActorTick.bCanEverTick = true;

	BlockMesh = CreateDefaultSubobject<UStaticMeshComponent>(TEXT("BlockMesh"));
	RootComponent = BlockMesh;
}

void ABuildingBlock::BeginPlay()
{
	Super::BeginPlay();
}

void ABuildingBlock::Tick(float DeltaTime)
{
	Super::Tick(DeltaTime);
}

void ABuildingBlock::SnapToGrid(FVector GridLocation)
{
	// Snapping logic
	FVector SnappedLocation = FVector(FMath::RoundToInt(GridLocation.X / 100.0f) * 100.0f,
										FMath::RoundToInt(GridLocation.Y / 100.0f) * 100.0f,
										GridLocation.Z);
	SetActorLocation(SnappedLocation);
}

void ABuildingBlock::PlaceBlock(FVector Location)
{
	SetActorLocation(Location);
}

In this code, the SnapToGrid function ensures that the building blocks align to a specific grid, making it easier for players to build. The PlaceBlock function allows the block to be placed at a specific location when confirmed.

2. Physics Simulation

The building blocks should have realistic physics, including gravity and collision detection.

// Adding Physics to the Building Block
BlockMesh->SetSimulatePhysics(true);
BlockMesh->SetMassOverrideInKg(NAME_None, 50.0f);  // Setting mass to 50kg

This snippet adds physics simulation to the blocks, making them fall, react to gravity, and collide with other objects. The SetMassOverrideInKg function gives the block a specific weight, allowing for complex interactions.

3. Resource Management

In a typical simulation, players need resources to build. Let’s say the player needs wood to place a block.

// ResourceManager.h
#pragma once

#include "CoreMinimal.h"
#include "GameFramework/Actor.h"
#include "ResourceManager.generated.h"

UCLASS()
class MYGAME_API AResourceManager : public AActor
{
	GENERATED_BODY()

public:
	// Sets default values for this actor's properties
	AResourceManager();

protected:
	virtual void BeginPlay() override;

public:
	UPROPERTY(EditAnywhere)
	int32 WoodCount;

	void DeductWood(int32 Amount);
};

// ResourceManager.cpp
#include "ResourceManager.h"

AResourceManager::AResourceManager()
{
	PrimaryActorTick.bCanEverTick = true;
	WoodCount = 100;  // Start with 100 wood units
}

void AResourceManager::BeginPlay()
{
	Super::BeginPlay();
}

void AResourceManager::DeductWood(int32 Amount)
{
	if (WoodCount >= Amount)
	{
		WoodCount -= Amount;
	}
	else
	{
		// Handle resource shortage
		UE_LOG(LogTemp, Warning, TEXT("Not enough wood!"));
	}
}

This code manages the player’s available resources, ensuring they need to gather more materials before building.

4. Destruction System

Simulating the destruction of buildings adds another layer of realism. Here’s an example of a simple structure destruction system.

// Adding destruction on impact
void ABuildingBlock::OnHit(const FHitResult& Hit)
{
	// Example logic for destroying a block when hit
	if (Hit.GetActor())
	{
		Destroy();
	}
}

This function can be bound to the OnHit event of the actor, where it destroys the building block when it collides with something.

5. UI Integration

Building systems also need to integrate with the UI to allow players to interact with the system easily. A simple button interaction might look like this:

// Triggered when the player selects a block to place
void ABuildingBlock::OnPlayerSelect()
{
	// Display placement preview
	UE_LOG(LogTemp, Log, TEXT("Block selected, ready for placement."));
}

In an actual game, this function would trigger a visual preview of the building block, allowing the player to see where the block will be placed.

Advantages and Disadvantages of This System

Advantages:

1. Dynamic Interaction: The system allows for real-time building, with physics-based interactions.
2. Resource Management: Adds complexity and strategy, as players must manage resources to construct.
3. Customization: Highly customizable — developers can extend it with new building types, structures, or even environmental damage.

Disadvantages:

1. Performance Impact: Handling large numbers of dynamic objects with physics can lead to performance issues.
2. Complexity: The system can get complex very quickly, especially when managing all the elements such as physics, resource gathering, and UI.

Conclusion

In this article, we’ve explored how to build a complex architecture system in Unreal Engine, integrating object placement, snapping, resource management, physics simulation, and a destruction system. The examples provided should give you a solid starting point to implement a fully functional and interactive building system in your simulation game.

This system offers a robust foundation for any simulation, survival, or strategy game, providing a realistic and immersive building experience for players. By incorporating these features, you can create a more engaging game world that players will love to interact with.