Create Amazing AI Roads in Unreal Engine

Table of Contents:

1. Introduction
2. Setting up the Spline Component
3. Creating the Generator Blueprint Actor
4. Adding Spline Properties Function
5. Constructing the Generator Blueprint Actor
6. Creating the Path Blueprint Actor
7. Making the Path Blueprint Actor Interactive
8. Adding Child Actor Component in the Generator Blueprint Actor
9. testing the Generated Road
10. Conclusion

Introduction

In this Tutorial, we will explore how to use a spline component to draw an AI road in Unreal Engine. By following the steps outlined in this tutorial, you will be able to create a spline-based road system that allows vehicles to automatically follow the generated road. We will start by setting up the spline component and creating the necessary blueprint actors. Then, we will add functionality to the road and test its capabilities. So, let's get started and create an amazing AI road system!

Setting up the Spline Component

To begin, we need to set up a spline component to serve as the basis for our AI road. In an empty folder, create a new blueprint class actor and name it "Generator". Add a spline component to the generator blueprint actor. We will also need some variables for the mesh and mesh length. Add a static mesh object reference variable and set its default value to a street mesh. Additionally, add a float variable for the mesh length, with a default value of 800. Make both variables public.

Creating the Generator Blueprint Actor

Next, let's go to the event graph of the generator blueprint actor. Delete the default nodes and create a new function called "Get Spline Properties at Index". This function will take an index as an input and will extract the start position, start tangent, end position, end tangent, and transform of the spline at the specified index. Connect the spline component to the "Get Location at Distance Along Spline" node to retrieve the start position, start tangent, end position, and end tangent. Finally, connect the spline component to the "Get Transform at Spline Point" node to get the transform. Save this function for later use.

Constructing the Generator Blueprint Actor

Now, let's move on to the construction script of the generator blueprint actor. Here, we will use a loop to iterate through the spline points of the spline component. First, use the "Get Number of Spline Points" node to get the total number of spline points. Subtract 2 from the return value to exclude the start and end points. Then, create a for loop that iterates from 0 to the total number of spline points. Inside the loop body, add a spline mesh component. Set the static mesh of the spline mesh component to the new mesh variable. Enable collision with "Query Only". Call the "Get Spline Properties at Index" function and pass the loop index as the input. Set the start and end values of the spline mesh component with the returned position values. Finally, enable "Update Mesh" to Visualize the road.

Creating the Path Blueprint Actor

Now, let's create another blueprint actor called "Path" for our road. Add a spline component to the path blueprint actor. In the event graph, delete the default nodes. Next, add a box collision component to the path blueprint actor. Adjust the size of the box collision component as per your requirements. In the event graph, add an "On Component Begin Overlap" event and connect it to a node that recasts to the AI vehicle blueprint actor (e.g., AI Firebird). In the recast node, call the "Set Active Path" function and connect the spline component to the active path. This will ensure that the AI vehicle follows the generated road.

Making the Path Blueprint Actor Interactive

To make the path blueprint actor interactive, we need to add it as a child actor component in the generator blueprint actor. In the construction script of the generator blueprint actor, add a node to "Add Child Actor Component". Set the relative transform of the child actor component to the path blueprint actor. Enable manual attachment and set the child actor class to the path blueprint actor. Now, the path blueprint actor will be added to each road part as a child component.

Adding Child Actor Component in the Generator Blueprint Actor

Now that we have added the child actor component in the generator blueprint actor, we can move the spline component to the desired location within the box collision component. Adjust the position of the selected point along the mesh length variable (e.g., 800). This value can be tweaked to fit the desired road aesthetics.

Testing the Generated Road

Let's test the generated road and its functionality. Place the generator blueprint actor in the scene and observe the road being drawn. Hold the "Alt" key and move the mouse to create curves on the road. Place the AI vehicle blueprint actor on the road and hit play. Watch as the vehicle drives along the road, following its curves and twists.

Conclusion

Congratulations! You have successfully created an AI road system using spline components in Unreal Engine. By using the generator blueprint actor and the path blueprint actor, you can now create complex road networks for AI vehicles to navigate. Experiment with different mesh lengths, spline adjustments, and road aesthetics to create unique and realistic road systems. Don't forget to test and iterate to achieve the desired results. Have fun creating amazing virtual worlds with AI-controlled roads!

Highlights

• Create an AI road system using spline components in Unreal Engine
• Draw roads with curves and twists for AI vehicles to follow
• Customize the mesh length, spline adjustments, and road aesthetics for unique road systems
• Test and iterate to achieve the desired results
• Enhance virtual worlds with realistic and interactive road networks

FAQ

Q: Can I use any mesh for the road? A: Yes, you can use any mesh of your choice for the road. Simply assign the desired mesh to the static mesh variable in the generator blueprint actor.

Q: Can I create multiple roads with different properties? A: Yes, you can create multiple generator blueprint actors with different properties, such as mesh lengths and spline adjustments, to generate different roads in your scene.

Q: How can I make the AI vehicle follow the generated road? A: Place the AI vehicle blueprint actor on the generated road and ensure that the "Set Active Path" function is connected to the "On Component Begin Overlap" event in the path blueprint actor. This will allow the AI vehicle to follow the generated road.

Q: Can I add additional functionality to the road system? A: Yes, you can further enhance the road system by adding features like speed limits, traffic lights, and lane changes. Explore Unreal Engine's capabilities and experiment with different functionalities to create a realistic road network.

Q: Is it possible to create bridges or tunnels with the road system? A: Yes, you can create bridges or tunnels by adjusting the spline component and mesh placement in the generator blueprint actor. Manipulate the spline points and adjust the meshes accordingly to create these unique road elements.