Space3d: a Rust 3D engine built for AI agents

SpaceCorps · 16 October 2026 · Engine

Space3d is the engine behind SpaceCorps 2027. One Rust codebase runs on desktop, web, Android and iOS, renders a million instances in one scene, never blocks a frame on I/O, and can be run, tested and verified headlessly by an AI agent.

38-second tour. Footage is real SpaceCorps 2027 gameplay rendered by Space3d.

A million instances, measured

1,000,000

Instances in one scene

~1,780

Frames per second

513 KiB

Uploaded per frame

Measured on 16 October 2026 with examples/instancing_million (release build, Apple M4 Max, Metal, GPU multi-draw path, run unthrottled without vsync, which is why it exceeds the 120 fps vsync-limited figure in our docs): 1,000,000 instances in one explicit instance buffer, culled on the GPU, with a travelling wave that rewrites a band of 16,384 instances per frame through dirty-range uploads. Window size and scene are the example's defaults, so treat it as a rendering-throughput figure, not a game benchmark.

ECS and fixed tick

Simulation runs on a deterministic fixed tick (60 Hz by default) decoupled from the frame rate. In the engine's own benchmark, one tick over 100,000 entities with transform propagation takes about 0.8 ms on the same machine (criterion median; the run was noisy, range 0.65–1.01 ms).

Never block the frame

File, network and database I/O return tasks; CPU-heavy work goes to a compute pool. In the async-loading example (a debug build with simulated network latency of 0.2–1.6 s per asset), 14 assets stream in over about 1.4 s while around 155 frames render and the longest frame stays near 17–22 ms.

Built for agents

Headless TestApp: run the engine without a window and without stealing focus.
Tick-exact input scripts: keyboard, mouse, touch and gamepad, recorded from a real session and replayed in a test.
Golden screenshots in cargo test: visual regressions fail CI with a diff image and an HTML report.
AGENTS.md: the engine's rules are written for coding agents as well as humans.

What we are not claiming. We have not benchmarked Space3d against Unity or Unreal, and we do not claim it is faster than either. Unity's DOTS in particular is a serious, highly optimised ECS. We will publish a like-for-like comparison, with the harness, when we have run one.

Where it runs

Desktop, web (wasm), Android and iOS from one codebase, with a space3d CLI that scaffolds, builds for each platform, serves the web build and publishes releases. Space3d is proprietary; the SpaceCorps 2027 game that ships on it is downloadable.