G7 Engine

The engine, and what happened to the first attempt

Asks Which engine should show Situ’s data in 3D and let a player act in it?

Decision Unreal Engine 5 (researcher decision), version 5.8. City Sample is not built on for now.

Stands A decision. A first set of engine plugins was built and then withdrawn (2026-10-28); the engine work starts again at stage 2.

Leaves out Play in a web browser: Unreal has not exported to the browser since version 4.24.

Trace The game, stage by stage

Unreal in Situ

version	5.8
earlier versions of Griffintown built in it	four (V1 to V4)
current project	a new, empty project, started 2026-10-28

Why not City Sample, for now

City Sample is Epic’s demonstration city, with traffic and crowds. In earlier prototypes I could not control its plugins well enough to use them for Situ. That may change with closer study of how they work, so I keep it as something to study, and do not build on it for now.

A first attempt, withdrawn

From 2026-10-22 to 2026-10-28 a first set of small engine plugins was built. They read the G1 World files: one drew the buildings from their footprints and heights, one the ground, one the raised sidewalks, and a core plugin read the files and converted the frame. Seventeen automated tests passed, and the buildings stood where the files put them.

Two ways of colouring parks, plazas and water on the ground were tried, and neither worked. Laid on the ground as separate sheets, overlapping pieces flickered. Painted into the 1 m terrain grid, every edge turned into steps, because the grid runs east and north while the streets run at about 62 degrees.

The work was withdrawn on 2026-10-28, and a new, empty project was started.

What stays	Where
the G1 files and their ledger	G1 World
the file formats, as a draft	Formats

What happens next

The engine work starts again at stage 2: one building, followed from QGIS into Unreal and checked against its source.