uwsbel

Entry point for FSI-coupled hybrid plans (plan_type=fsi_in_scene) — any scene combining SPH fluid (water tanks, dam-break, wave channels) with multi-body dynamics, optionally with a wheeled vehicle. Pick this over mbs_in_scene whenever the plan involves a fluid domain (scene_objects with domain_type starting "sph_") or an FSI body registration (scene_objects with fsi_registration set). Routes to fsi/sph (always), veh/wheeled_vehicle (when vehicle present), and enforces FSI-specific invariants distinct from generic mbs_in_scene rigid scenes.

Entry point for rigid-body hybrid plans (plan_type=mbs_in_scene) combining a robot or vehicle with scene assets — NO fluid coupling. Routes to the correct domain skills and defines only high-level invariants. Use core/fsi_in_scene instead when the plan involves SPH fluid or FSI body registration.

Entry point for pure multi-body simulation plans (plan_type=mbs). Routes the agent to the correct mechanics, system, and camera skills and defines only high-level invariants.

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.

Set up SPH-based Fluid-Structure Interaction (FSI): create ChFsiFluidSystemSPH and ChFsiSystemSPH, configure fluid and SPH parameters, seed fluid particles with hydrostatic initialization, add container BCE boundary markers, register floating rigid bodies, optionally couple with a wheeled vehicle, and advance with sysFSI.DoStepDynamics(dT).

Translate a `geometry_relations` entry from the plan into correct PyChrono coordinate code. Read this whenever the plan declares a relation_name you have not previously encoded, and especially BEFORE writing SetPos / camera placement for any body that participates in a multi-body geometric constraint. Each subsection below is one canonical pattern named exactly as it appears in `plan.geometry_relations[i].relation_name`.

Create rigid bodies with mass, geometry, collision shapes, and visual assets.

Enable contact detection using the correct contact material for NSC or SMC systems.

Quaternion creation, component access, and Euler angle conversion in PyChrono

Run the time-stepping loop, collect data, and post-process results with matplotlib or CSV.

Irrlicht visualization — visual shapes (mesh, line, spring), materials, GUI overlays, path rendering, and collision debug.

Create rigid bodies with mass, geometry, collision shapes, and visual assets.

Enable contact detection using the correct contact material for NSC or SMC systems.

Apply custom forces/torques to rigid bodies via accumulators, and impose prescribed motion or force between two bodies using ChLinkMotor classes. Covers axis-aware force/torque application and paired internal reactions.

Create and configure a PyChrono ChSystem, gravity, contact method, and solver.

Joint topology, kinematic constraints, and elastic links for MBS. Covers revolute, prismatic, motors, springs, axis-aware joint frames, and correct topology for mechanisms with ground pivots and fixed guides.