PhysicsServer3DManager in Godot – Complete Guide

Getting to grips with the underlying systems that make a game engine tick can be a transformative experience for any developer, no matter their level of expertise. In the case of the Godot Engine, understanding the PhysicsServer3DManager presents an opportunity to delve deeper into what makes your 3D games behave the way they do. This tutorial is about PhysicsServer3DManager, a foundational class in Godot 4 that you’ll likely encounter when you take your game development skills to new heights with Godot’s powerful 3D engine. Keep reading to discover how this enigmatic class operates and why getting a handle on it could be a game-changer for your projects.

What is PhysicsServer3DManager?

PhysicsServer3DManager is a class in the Godot Engine that serves as a central point for managing different implementations of the 3D physics engine. Essentially, it’s a system that allows you to register and manage different physics servers – the components that handle all the calculations and dynamics involving physics in your game world.

What is it for?

This class might seem a bit abstract at first, but it’s incredibly useful for game development. With the PhysicsServer3DManager, developers can create custom physics engines or modify existing ones to alter the behavior of physics in their games, all before the game starts. This offers a level of flexibility and control that can be crucial for creating a unique gameplay experience.

Why Should I Learn About It?

Venturing into the understanding of PhysicsServer3DManager equips developers with the capabilities to optimize and tweak the game’s physics to their exact preferences, and it also illustrates a more in-depth aspect of the Godot Engine. By learning how to use this class, you’ll gain:

– A stronger grasp on how physics are managed in 3D games.
– The ability to customize the physics system for specific game requirements.
– Deeper insights into the internal workings of the Godot Engine, empowering you to create more sophisticated and optimized games.

This knowledge is not just theoretical — it’s a practical toolkit that could be the difference between a good game and a great one. Let’s dive into the coding tutorial sections, where we’ll explore PhysicsServer3DManager with tangible examples.

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Setting Up PhysicsServer3DManager

Before you start flexing your customization muscles, you need to know how to set up and access the PhysicsServer3DManager in Godot 4. Let’s start with how to access the manager and see which physics engine it’s using by default.

var physics_server_name = PhysicsServer3DManager.get_singleton().get_default_physics_name()
print("The default physics engine is: ", physics_server_name)

Once you’ve accessed the PhysicsServer3DManager, you might want to change the physics engine being used. The example below demonstrates how to switch between registered physics engines:

# Assuming you have multiple physics engines registered, such as "GodotPhysics" or "Bullet"
PhysicsServer3DManager.get_singleton().set_active_physics("GodotPhysics")

However, most of the time, you’ll stick with the default provided by Godot. It’s important to note that you should set the active physics before the game scene starts, as changing the physics engine during gameplay can lead to unpredictable results.

Customizing the Physics Engine

Now let’s jump into how you can get your hands dirty by customizing the default physics engine. Say you want to adjust the gravity for your entire game without manually changing each physics body. The snippet below shows how to do that:

# Customize the gravity for the entire 3D scene (measured in meters/sec^2)
var custom_gravity_vector = Vector3(0, -9.8, 0) # This is the standard Earth gravity vector
PhysicsServer3DManager.get_singleton().physics_set_param(PhysicsServer3D.PHYSICS_PARAM_GRAVITY, custom_gravity_vector)

In the event you need a physics environment without any gravity at all, like for a space simulator, you can turn it off completely with:

# Set zero gravity
PhysicsServer3DManager.get_singleton().physics_set_param(PhysicsServer3D.PHYSICS_PARAM_GRAVITY, Vector3())

There may be instances where you’ll want to customize the physics properties of individual objects. Here’s how you can alter the physics material for a physics body object:

var physics_material = PhysicsMaterial.new()
physics_material.friction = 0.5
physics_material.bounce = 0.2

# Assign the custom physics material to a RigidBody3D node
var rigid_body = $RigidBody3D
rigid_body.physics_material_override = physics_material

Understanding Physics Layers and Masks

Physics layers and masks add another layer of control over interaction between objects in your game. For example, you might have a character that shouldn’t be affected by certain environmental hazards. Here’s how you manage physics layers:

# Set the physics layer
var collision_layer = 1 << 2 # This sets the object to the third layer
$RigidBody3D.collision_layer = collision_layer

# Set the collision mask to detect collisions only with objects in the first and second layers
var collision_mask = (1 << 0) | (1 << 1)
$RigidBody3D.collision_mask = collision_mask

This will ensure that your RigidBody3D node will only interact with objects that are set to the layers defined in the collision mask.

Each of these code snippets outlines fundamental ways to interact with Godot’s PhysicsServer3DManager. Remember, these customizations are a powerful tool in a game developer’s arsenal and can significantly impact the feel and mechanics of your game. Use them wisely to achieve the desired outcome in your game’s physical interactions.Managing physics in a 3D environment can be complex, but Godot’s PhysicsServer3DManager offers a multitude of functions to give developers extensive control. Here are several practical code examples showcasing different aspects of physics management that you might encounter when refining your game.

Adjusting Physics Properties Globally

Sometimes, you might want to modify global properties such as the physics step or the sleep threshold. Here’s how you could adjust these settings:

# Set the fixed physics step, which is the amount of time each physics simulation step takes
PhysicsServer3DManager.get_singleton().physics_set_param(PhysicsServer3D.PHYSICS_PARAM_FIXED_FPS, 60)

# Change the sleep threshold, which determines when a physics body can go to 'sleep' and stop being simulated to save CPU
PhysicsServer3DManager.get_singleton().physics_set_param(PhysicsServer3D.PHYSICS_PARAM_BODY_SLEEP_THRESHOLD, 0.1)

Defining Areas with Different Physics Properties

In more complex games, different areas or zones may have their own set of physics rules. For creating an area with different gravity, you would set up an Area3D node like this:

# Create a custom gravity vector specifically for this area
var area_gravity_vector = Vector3(0, -4.9, 0)

# Set up the Area3D node's gravity
$Area3D.gravity_vector = area_gravity_vector
$Area3D.override_gravity = true
$Area3D.gravity = 5 # This is the force scale for the gravity

This setup would give objects inside this Area3D node half the standard terrestrial gravity.

Creating Custom Physics Shapes

The shape of your physics bodies can drastically change how they interact within your game. Creating a new collision shape can be done programmatically:

# Create a new box shape resource
var box_shape = BoxShape3D.new()

# Set the box dimensions
box_shape.extents = Vector3(2, 2, 2)

# Use the shape in a RigidBody3D's CollisionShape3D node
$RigidBody3D/CollisionShape3D.shape = box_shape

Shapes aren’t limited to boxes, of course. Godot provides Cylinders, Capsules, Planes, and more, all of which are useful for achieving realistic physics behavior.

Raycasting for Physics Interactions

Raycasting is an essential tool for detecting objects in the line of fire, determining sight lines, or triggering events from a distance. Here’s a basic raycast setup:

# Perform a raycast from the origin to 10 meters forward
var from = Vector3(0, 0, 0)
var to = Vector3(0, 0, 10)
var result = PhysicsServer3DManager.get_singleton().raycast(from, to)

if result:
    print("Raycast hit: ", result.collider.name)

This example assumes that your collision layers and masks are correctly set so that the raycast can detect the colliders.

Responding to Physics Events

In Godot, you can set up callbacks to respond to various physics events like collisions or entering/leaving areas. For instance, to detect when a body enters an area:

func _on_Area3D_body_entered(body):
    print("Body entered: ", body.name)

This callback function would be connected to the `body_entered` signal of an Area3D node, and would automatically be called when a physics body enters its space.

Managing the intricacies of 3D physics can seem daunting, but with the Godot Engine’s robust PhysicsServer3DManager, you have an array of tools at your disposal. These examples provide a practical foundation for manipulating physics properties both globally and locally. You’ll find that a deep understanding of these systems will empower you to craft dynamic, believable 3D worlds that respond to players’ actions in intuitive ways.Continuing with our exploration of physics in Godot, let’s dive into more advanced functionalities and how they can be implemented in your game. The examples provided will demonstrate handling physics queries, controlling physics bodies, and simulating custom forces.

Handling Physics Queries with PhysicsServer3DManager

Physics queries are vital for game logic, as they allow you to ask the physics engine about the state of the world. Here’s how you can use PhysicsServer3DManager to perform a shape cast, which is similar to a raycast but uses a shape instead of a line:

# Define the shape for the shape cast, for example, a sphere
var sphere_shape = SphereShape3D.new()
sphere_shape.radius = 1.0

# The starting and ending points of the shape cast
var from = Transform3D(Basis(), Vector3(0, 1, 0))
var to = Transform3D(Basis(), Vector3(0, -1, 0))

# Perform the shape cast
var shape_cast_result = PhysicsServer3DManager.get_singleton().shape_cast(sphere_shape, from, to)

if shape_cast_result.collider:
    print("Shape cast hit: ", shape_cast_result.collider.name)

This technique is useful for detecting objects within a volumetric area rather than just along a line.

Controlling Physics Bodies Programmatically

To directly control physics bodies, you might want to bypass the physics engine’s standard operations in certain scenarios. For example, to reposition a RigidBody3D instantly, you can use the following code:

# Get a reference to the RigidBody3D node
var rigid_body = $RigidBody3D

# Move the body to a new position
rigid_body.global_transform.origin = Vector3(10, 0, 0)

Do note that this will instantaneously move the body, without any regard for physics interactions on the way to its new position.

Now, let’s look at how to apply a central impulse to a RigidBody3D, which can be used to simulate an immediate force like an explosion:

# Apply a central impulse
rigid_body.apply_central_impulse(Vector3(0, 100, 0))

This would result in the body being propelled upwards. Central impulses act on the body’s center of mass, applying equal force in all directions.

Simulating Custom Forces and Torques

In addition to utility functions, you can simulate your own forces on RigidBody3D nodes. To apply a force at a specific point of the body, you might use the following:

# Apply a force at a specific point
rigid_body.apply_impulse(Vector3(1, 0, 0), Vector3(0, 50, 0))

This will apply a force of 50 on the Y-axis at a point one unit along the X-axis from the center of the body.

Moreover, you can exert a torque on the body, causing it to rotate around an axis:

# Apply a torque
rigid_body.apply_torque_impulse(Vector3(0, 100, 0))

This torque will cause the body to start spinning around the Y-axis.

SoftBody Dynamics in Godot

SoftBody3D nodes represent soft body physics, such as cloth and jelly. Here’s an example of how to create and interact with a SoftBody3D node programmatically:

# Assuming the SoftBody3D node is a child of the current scene
var soft_body = $SoftBody3D

# Set the soft body parameters, like its mass
soft_body.mass = 0.8

# Control the level of soft body simulation detail
soft_body.simulation_precision = 5

These SoftBody3D settings are crucial to fine-tune the simulation to achieve realistic behavior for non-rigid objects.

Every example shown here illustrates the power and flexibility of the Godot Engine’s physics system. Through PhysicsServer3DManager, Godot offers the control necessary to fine-tune physical simulations to your specific needs, adding a level of precision and realism to your 3D games that can truly engage players. Developing a strong understanding of these systems not only makes you a better game developer but also opens up a world of possibilities for the types of experiences you can create.

Where to Go Next with Your Godot Journey

Mastering the foundational elements of Godot, like PhysicsServer3DManager, is just the beginning of your adventure in game development. But where do you go from here? The exciting path ahead is filled with opportunities to deepen your understanding and expand your creative toolkit.

If you’re eager to continue learning and start building your own games, our Godot Game Development Mini-Degree is the perfect next step. This comprehensive course collection will guide you through building several games with Godot 4 and arm you with a wide range of skills. From crafting dynamic 2D and 3D environments to programming gameplay mechanics, you’ll gain hands-on experience that is critical in the game development industry. Although we don’t cover the PhysicsServer3DManager directly, the Mini-Degree will solidify your understanding of Godot’s systems and help you create engaging and interactive gaming experiences.

For those who want to explore more specific topics or find tutorials that match their current level of expertise, our broad selection of Godot courses offers content for all learners, from beginners to seasoned developers. With Zenva, you can progress from the basics to advanced techniques at your own pace, developing your skills and building a portfolio that showcases your capabilities.

The road to becoming a proficient game developer is exciting and rewarding. Whether you’re looking to sharpen your current skills or delve into new topics, we’re here to support your continuous learning journey. Keep experimenting, keep coding, and most importantly, keep creating. The world of game development awaits!

Conclusion

Embarking on the journey of mastering Godot and its robust physics system through the PhysicsServer3DManager can seem like a challenging task, yet the creative possibilities it unlocks are boundless. Armed with the knowledge of how to manipulate and customize the physics in your games, you now stand at the threshold of turning your unique visions into reality. Whether you’re designing intricate worlds with precise physics interactions or simply seeking to add a new layer of polish to your projects, your newfound skills will serve as the cornerstone of your game development endeavors.

But remember, this is just the start! Continue to build, innovate, and refine your craft with the tools and teachings provided in our Godot Game Development Mini-Degree. Let us be your guide as you navigate through the exhilarating landscape of game design and development. The canvas of digital creation is vast, and we can’t wait to see what you’ll bring to life next.

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