Start with the lot. Then test the spacecraft.
The cyan outline is the whole small-lot scenario. The green dashed plate is the selected buildable footprint. Modules snap inside that envelope, while edge pieces such as loading and external stairs can sit on the service edge.
Boundary
Simulation first. Approval later.
Floor Plan
Floor 1 - 0.6m grid
Choose a module, then click the grid. Click an existing module to select it.
Agent Handoff
Export the layout as JSON or Markdown.
JSON restores the exact simulator state. Markdown gives agent teams the scenario, module totals, rail assumptions, habitat metrics and future simulation prompts.