AI Built a City in Unreal Engine, but the Comments Are Asking Whether It Can Change Just One Building

Someone used AI to build a complete medieval city in Unreal Engine. The city walls, stone bridge, red-roofed, white-walled terraced houses, and the people in the central square were all generated.

This is the work of X user Shikhar. All assets were made in Blender, and the scene was assembled by Opus 5.5 in Unreal Engine. When Meng To reposted it, he remarked that the amount of detail is staggering; Unreal MCP for Claude Code became his entry point into game development next, and the repository is under EpicGames' GitHub organization.

Shikhar's own words are more interesting: This is the worst it will ever be. In other words, the model will keep iterating, and today's city will be the lower bound for the future.

But the liveliest part of the comments is not the result itself. Shikhar added that his workflow now barely uses MCP. The approach is to use Python scripts to directly control headless Unreal Editor instances, mainly writing C++ code to build things. This pipeline is memory-hungry; if there isn't enough, subagents will crash the machine. In his view, Blender is essential and unavoidable.

Some people also fell into README pitfalls. A commenter pointed out that you must first enable the AllToolsets plugin, otherwise the server exposes no tools at all; the editor must stay running and call ModelContextProtocol.StartServer. execute_tool_script essentially runs arbitrary Python inside the editor, so don't casually add --dangerously-skip-permissions.

Technical questions center on visual verification. Someone asked whether MCP returns a viewport screenshot after each edit. From scene text descriptions alone, layout problems simply cannot be seen. Others worry that once many objects are placed, lighting will quickly turn into a mess.

The most practical challenge comes from Jatin Garg: the real test is whether Claude can change just one building without rebuilding the entire city. That gets at the gap between a demo and engineering.

Another reply offers a different perspective. A user said 3D is where "talking to it" truly lands. Without reading code, you stare at the scene and say directly, "it's upside down" or "the bridge should land on this side," and Claude Code edits while letting you watch. He fixed a batch of bugs in a 3D map viewer this way.

Building the city itself is the automation of manual labor. What the comments are really worried about lies elsewhere: local edits, rollback, lighting stability, and whether Blueprints are reliable. These are the stretch of road from a good-looking video to something actually usable. Shikhar mentioned that he thought many times about stopping work and waiting for the next-generation model, but 5.5 never let him down.