Custom Collision and Navigation

This article covers how to generate custom collision for Navigation

This is a Work in Progress article.

Overview

In the cases where the basic Collision generated by Unreal Engine does not conform to the shape, this article will cover the process of using custom Collision.

Unreal Engine Complex Collision

[Unreal Engine Convex Decomposition will try to approximate a mesh to be used for Collision through simplifying the mesh around a few user-specified parameters]

Figure 1.0 - Unreal Engine Complex Collision

1. Open the piece of content using the StaticMeshEditor

2. Enable the Convex Decomposition window if disabled through Window > Convex Decomposition

3. Hull Count and Max Hull Verts can be increased to allow for more points, allowing for it to capture more features of the original.

4. Hull Precision is the accuracy.

Custom Collision

[When Unreal's Complex Convex Decom doesn't work, Rhino can be used to create a simplified mesh that will function as collision, this is a common process using Unreal Engine, of creating the simplest surface mesh representation of an object and using it as an invisible collision only actor]

1. In Rhino, re-model or [ReduceMesh] to a very low level and simple mesh.

2. Export as an .fbx

3. Import it into Unreal Engine. Uncheck Autogenerate Collision.

4. In the Static Mesh Editor, [Use complex collision as simple] in Collision Complexity

5. Add the collision mesh to the scene.

6. In Details panel Hidden Actor in Game, this hides the rendering of the geometry, but it's collision still applies.