[Feature request]: Provide world layout and flexible fidelity simulation setup from SiteEditor

Before proceeding, is there an existing issue or discussion for this?

• I have done a search for similar issues and discussions.

Description

We have a great visualization tool for setting up scenarios. However, we are not utilizing said tool in the prototype.

For systems running Nav2 natively, simulating the environment with at least a 2D LiDAR is essential, with potential interest in full end-to-end (E2E) testing. Conversely, for end-users working with VDA5050, simple event-driven simulations may suffice. While we can currently export simulations to Gazebo via rmf_simulation, expanding support to accommodate these additional use cases is highly desirable.

Implementation

• Milestone 1: Custom SDF World Export
  The most straightforward approach to achieving variable simulation fidelity is to support loading custom base Simulation Description Format (SDF) files. The legacy build pipeline in rmf_building_map_tools allows specifying a custom base SDF. Currently, the base SDF file is hardcoded here; introducing a user interface to select alternative base files should be relatively straightforward. Additionally, providing a collection of standard presets would be beneficial. (See https://github.com/open-rmf/rmf_site/pull/437)
• Milestone 2: Scenario Export
  Although scenarios can be created within the Site Editor, executing them end-to-end is not yet supported. Ideally, users should be able to export a complete ROS and Gazebo simulation with Nav2 integrated via a single button click.

Alternatives

Developing native simulation capabilities directly within the Site Editor is a complex undertaking due to the varying levels of fidelity required. Currently, established simulators like Gazebo and Isaac Sim make this not worth our time and effort.

Additional information

No response

Start by reviewing rmf_site_format/src/templates/gz_world.sdf, the legacy rmf_building_map_tools custom-base-SDF flow, and rmf_simulation's current export path. Define the scope for selecting SDF presets or custom files first, then assess the separate scenario-export milestone; done should include the requested Site Editor workflow and, for full export, a runnable ROS/Gazebo simulation with Nav2.