Carved stone halls under the mountain: a great gate cut into the mountainside with two dwarf guardians, a forge hall and its cutaway, which opens it to show the whole workshop inside; a smelter pouring molten metal, a mine headframe over its shaft and a home dug into a hill; hall walls, a doorway, a great pillar and floor tiles; mine tunnel timbering and lava channels that run in lines of any length, a chasm bridge over a river of lava, a gold and gem vein, glowing cave mushrooms and basalt columns; and the forge itself: a water-driven trip hammer, anvil, crucible and moulds, quench trough, ingots, an ancestor statue, mining tools, braziers, a chain lantern, an ale table and a rack of axes and hammers.

The hall walls and doorway join the village and castle walls on the 2 m grid, the hall floor joins the other paths and paving. One light runs through it all: fire, from forge-glow and molten metal to lava and fire-lit runes, each with a light marker for the World Builder's dusk and night.

Conventions: 1 unit = 1 metre, Y-up, models face +Z, pivot at the centre of the footprint on the ground. Modules are 2.0 m.