Bob The Burglar

Getting Bob The Burglar to Actually Work

Bob The Burglar is a standalone navmesh baking utility for Unreal Engine. That's the simple version. The practical version is that it exists because Unreal's built-in navmesh generation struggles with complex environments, dynamic geometry, and scenarios where you need precise control over what your AI can and cannot reach. The tool scans your level geometry and produces a navigation mesh optimized for pathfinding. I used it on a project where the default UE navstatic geometry approach kept creating floating islands that looked connected on paper but were practically unreachable for AI. The bake took about 45 minutes on a mid-range machine and produced a mesh with far fewer degenerate triangles than the standard exporter. That was the main draw for me.

Installing Bob The Burglar

You grab it from GitHub. The repository is maintained as a UE4 plugin, so you drop it into your project's Plugins folder rather than installing it globally. If you're working in UE5, check whether the version you pull supports 5.x natively. There have been compatibility patches over the years but they don't always apply cleanly. I ended up building it from source once because the precompiled binary was targeting an older engine snapshot and wouldn't load in my environment. After placing it in the right folder, restart the editor. You should see a new toolbar entry or menu option under Window if everything initialized correctly. If it doesn't appear, verify that your project's .uplugin file references the module name correctly. That's where most people get stuck on first install.

The actual workflow

Load your level. Make sure your static meshes are properly tagged as navigation geometry. By default, Bob The Burglar processes everything with the NavMesh tag enabled. You can adjust which actors are included through its settings panel. The default recast grid settings give reasonable results for indoor spaces, but you'll want to tune cell size and walkable slope before committing to a full bake. I run into issues most often with outdoor levels that have dense vegetation or scattered props. The tool tends to over-triangulate in those cases. My workaround has been to batch your landscape geometry into a single static mesh before baking, remove duplicate collision volumes, and set a higher cell size for open areas. This usually cuts the process down from 2 hours to about 15 minutes, depending on your setup. I've seen bakes on large outdoor levels exceed an hour with the defaults, which is frustrating when you're iterating. Once your settings are locked in, hit the bake button and wait. The output is a visible navmesh overlay in the viewport. You can then export it as a nav static mesh or let the engine consume it directly for AI pathfinding. Exported meshes are useful if you need to share the nav data across multiple levels or versions of a map.

One thing people miss is that the tool doesn't handle moving platforms or changing geometry. If your level has any runtime modifications to the environment, the navmesh becomes stale immediately. You either have to re-bake on the fly using runtime recast features, or you lock those geometry changes until the next bake cycle. This is a real limitation. There's a workaround involving scripting a periodic re-bake triggered by level events, but it adds overhead and complexity that most projects don't need unless they have substantial dynamic obstacles. If your project is primarily UE5 with a lot of procedural geometry, you might find the built-in navmesh tools adequate now. They've improved significantly. Bob The Burglar still has an edge when you need fine-grained control over tile size, region merging, and custom filter settings that the standard exporter doesn't expose as clearly.