Optimizing Collision in Unreal Engine: Simple vs. Complex

In this blog post, we dive into the realm of collision in Unreal Engine, specifically focusing on the differences between simple and complex collision meshes, how to set them up correctly, and why using complex collisions indiscriminately might not be the best idea. Let's explore the best practices to ensure efficient collision detection in your projects.

Understanding Collision Types

Simple Collision:

Automatically Generated: When importing static meshes into Unreal Engine, simple collision meshes are auto-generated by default.
Suitable for Convex Shapes: Ideal for objects with simple convex shapes like cubes, cylinders, etc.
Inefficient for Concave Shapes: Inadequate for objects with concave shapes like doorways, bridges with holes, etc.

Complex Collision:

Duplicated Static Mesh: Complex collision meshes duplicate the object's static mesh, potentially doubling the polygon load.
Inefficient and Inaccurate: Rendering the entire static mesh for collision detection can lead to inefficiency and inaccuracies in collision detection.

The Pitfalls of Using Complex Collision

While it may seem convenient to enable complex collision for all objects, it can significantly impact performance due to redundant polygon usage. Additionally, complex collision might not always align perfectly with the object's geometry, leading to unexpected collisions and inaccuracies in the game world.

The Solution: Custom Collision Meshes

To address the limitations of simple and complex collisions, creating custom collision meshes is the way to go. By following these steps, you can ensure accurate and optimized collision detection in your Unreal Engine projects:

Disable Automatic Collision Generation: Turn off the option to generate missing collision meshes during import.
Enable Customized Collision: Utilize custom collision meshes alongside your static meshes for precise collision detection.

Creating Custom Collision Meshes in Blender

In Blender, you can create custom collision meshes for objects with concave shapes like bridges, doorways, etc. By crafting low-poly proxy meshes that mimic the object's shape, you can achieve accurate collision detection without the overhead of complex collisions.

Steps to Create Custom Collision Meshes:

Design separate collision shapes for concave parts.
Name the collision objects with a specific naming convention (ucx_objectname_01, ucx_objectname_02, etc.).
Export the objects with custom collision meshes as an FBX file.

Implementing Custom Collision in Unreal Engine

After importing the FBX file into Unreal Engine, ensure that automatic collision generation is disabled. By using the custom collision meshes as both simple and complex collision types, you can achieve precise collision detection with minimal performance impact.

By following these practices, you can streamline collision setup in your Unreal Engine projects, enhancing both performance and accuracy in collision detection scenarios. Opt for custom collision meshes where needed to strike the right balance between efficiency and precision in your game environments.

Meet Tripo

Discover the capabilities of Tripo and unlock a world of possibilities:

Draft Model Generation: Instantly spark inspiration with our fastest models. Perfect for rapid prototyping and conceptualization, this feature lets you explore various designs or perspectives before diving into detailed modeling. Accepts both text and image input.
Refine Draft Models: Elevate the quality of your initial draft models into finely detailed creations. Seamlessly transition from conceptual drafts to high-resolution models, streamlining your creative workflow.
Model Animation: Bring your creations to life with automated animation. Transform static models into dynamic animations, enhancing presentations or digital experiences effortlessly.
Stylization and Conversion: Customize and convert your models with unparalleled ease. From transforming models into lego-like or voxel-based versions to supporting format conversion (USDZ or FBX), Tripo offers unique stylization options, ensuring compatibility across platforms and applications while injecting a creative twist into your projects.