sequenceDiagram
    participant User
    participant HeatChargeSimulation
    participant Validator as _warn_small_cylinder_radius
    participant GeomUtils as traverse_geometries
    participant Cylinder
    participant Logger as log.warning

    User->>HeatChargeSimulation: Create simulation with structures
    HeatChargeSimulation->>Validator: Validate structures field
    
    loop For each structure
        Validator->>GeomUtils: traverse_geometries(structure.geometry)
        GeomUtils-->>Validator: Yields nested geometries
        
        loop For each geometry
            alt geometry is Cylinder
                Validator->>Cylinder: Get radius_bottom
                Cylinder-->>Validator: r_bottom
                Validator->>Cylinder: Get radius_top
                Cylinder-->>Validator: r_top
                
                Validator->>Validator: Check if tapered (r_bottom != r_top)
                Validator->>Validator: Compute min_radius = max(MIN_GMSH_RADIUS, 0.01*max(abs(r_bottom), abs(r_top)))
                
                alt is_tapered
                    alt r_bottom < min_radius
                        Validator->>Logger: Warn about radius_bottom
                    end
                    alt r_top < min_radius
                        Validator->>Logger: Warn about radius_top
                    end
                else not tapered
                    alt r_bottom < min_radius
                        Validator->>Logger: Warn about radius
                    end
                end
            end
        end
    end
    
    Validator-->>HeatChargeSimulation: Return validated structures
    HeatChargeSimulation-->>User: Simulation created (with warnings)