scene

name	scene
description	Entry point for static scene plans (plan_type=scene). Routes the agent to the correct scene, system, and camera skills and defines only high-level invariants.
compatibility	pychrono >= 8.0
metadata	{"domain":"core"}

Core Skill: Scene

Use this skill when plan_type = "scene".

This core skill is a router and constraint layer, not a recipe catalog. It decides which child skills must be read and states scene-wide invariants that apply regardless of the specific asset family. Concrete asset-loading APIs, placement recipes, camera layouts, and scenario-specific code patterns belong to the owning child skills.

Responsibility

This core skill covers only:

• static mesh scenes with no robot, vehicle, or actuated body
• which child skills must be read before writing code
• global invariants such as world convention, system ownership, and rendering separation
• high-level dispatch to the child skill that owns the asset pipeline

This core skill does not define:

• task-specific scene layouts
• named office / offroad / furniture recipes
• concrete utility signatures beyond short category reminders
• exact asset placement or camera placement formulas

Required Skills — read these before writing code

Skill	Why it is required
mbs/system_create	Choose and configure the physical system, gravity, solver
vsg	VSG visualization window setup, camera, grid, sky, render loop
sens/camera	Sensor manager, setup_preview_camera, recorder loop integration, camera output behavior

Choose the owning scene skill

After reading this core skill, read the child skill that actually owns the asset family:

• Read the owning scene/* skill for the asset family in the plan.
• All assets must be implemented through project utilities from chrono_code.utils / chrono_code.utils.scene_assets.
• The child skill is authoritative for which utility helper to call for a given asset family.

If a child skill owns a utility or asset pipeline, that child skill is authoritative for the concrete API and code pattern.

Optional Skills — read if the plan requires them

Skill	When to read
mbs/body_creation	Manual body creation when not using a scene utility pipeline
mbs/collision	Contact material choice and collision shapes
planning/scene_coordinate_system	Scene predicate algebra and authored layout semantics
planning/asset_discovery	Discovering available assets and paths

Global Invariants

• Default world convention is Z-up unless a child skill explicitly owns a different convention.
• A static scene uses one physical system for all bodies, cameras, and visualization.
• VSG window viewpoint and sensor cameras are separate concerns:
  • vis.AddCamera(...) sets the interactive VSG window view
  • setup_preview_camera(...) creates actual sensor-camera output
• Do not call chrono.SetChronoDataPath() by default. Trust the default data path unless an owning child skill explicitly says otherwise.
• Choose one contact model and keep it consistent with the physical system and materials.
• vis.AddCamera(...) must be configured before vis.Initialize().

Routing Rules

• If the plan is a pure static scene with no driven body, stay in the scene family.
• Route to the owning scene/* child skill for the asset family in the plan.
• Do not invent a parallel asset-loading path in core; asset implementation must go through project utility functions owned by the child skill.
• If the request includes any robot, rover, vehicle, or actuated body, this is no longer a plain scene problem; route to core/mbs_in_scene.

Minimal Category-Level Reminders

• All scene assets should be implemented through project utility functions, not ad-hoc inline loaders.
• The owning child skill decides which asset utility helper is valid for that asset family.
• Sensor recording requires setup_preview_camera() from sens/camera; vis.AddCamera(...) alone is not enough.

What Core Must Not Contain

If you are writing or updating a core scene skill, do not place these here:

• concrete asset-family recipes
• room-size-specific camera formulas
• exact AssetDescriptor(...), create_asset_body(...), or add_visual_assets(...) recipes
• ground-construction recipes owned by a child scene skill

Those belong in the owning child skills.