What are the pros and cons of using Unity's built-in physics engine vs Unreal's PhysX for mobile games?

1 Unity's built-in physics engine

Unity's built-in physics engine is based on NVIDIA's PhysX 3.4, which is a widely used and reliable physics middleware. Unity's physics engine offers a simple and intuitive interface for creating and manipulating rigid bodies, colliders, joints, and triggers. You can also use Unity's scripting API to access and modify the physics settings and behaviors. Unity's physics engine is well integrated with its animation, audio, and UI systems, and supports both 2D and 3D physics.

However, Unity's physics engine also has some drawbacks. For instance, it does not support soft bodies, cloth, or fluid simulation, which might limit your creative options. It also has some performance issues on mobile devices, especially on older or low-end models. You might need to optimize your physics settings, such as reducing the number of physics objects, lowering the physics timestep, or using physics layers and collision matrix. Additionally, Unity's physics engine might not be compatible with some third-party plugins or assets that use a different physics engine.

2 Unreal's PhysX

Unreal's PhysX is also based on NVIDIA's PhysX, but it uses a newer version (4.1) that has some improvements and features over Unity's version. Unreal's PhysX supports soft bodies, cloth, and fluid simulation, as well as advanced collision detection and response. You can use Unreal's visual scripting system, Blueprint, to create and control physics objects and events. Unreal's PhysX is also integrated with its animation, audio, and UI systems, and supports both 2D and 3D physics.

However, Unreal's PhysX also has some drawbacks. For instance, it has a steeper learning curve than Unity's physics engine, and requires more coding and debugging skills. It also has some compatibility issues with some mobile platforms, such as iOS and Android, which might require you to use a different physics engine or disable some features. You might also need to optimize your physics settings, such as reducing the number of physics objects, lowering the physics timestep, or using physics layers and collision matrix.

3 Choosing the best physics engine for your mobile game

When selecting the best physics engine for your mobile game, you should consider the genre and style, performance and optimization, and platform and compatibility. Depending on your game's design, goals, and target audience, you might need more or less physics features and realism. Additionally, you should think about how well your game runs on mobile devices, how much battery and memory it consumes, and how smooth and responsive it is. Furthermore, you should determine if the mobile platforms you are targeting are compatible with your chosen physics engine and if they support all the physics features you need. Ultimately, by evaluating the advantages and disadvantages of Unity's built-in physics engine vs Unreal's PhysX for mobile games, you can make a decision that best suits your game's needs and expectations.

4 Here’s what else to consider

This is a space to share examples, stories, or insights that don’t fit into any of the previous sections. What else would you like to add?