Extension helper for ArchPlan that exposes all roof parts. It defines a single extension method AllRoofs that returns the plan's parts cast to ArchRoofPart, optionally filtered by an ArchKinds table.
using System.Collections.Generic;
namespace Sunless.Architecture;
public static class ArchPlanRoofs
{
public static IEnumerable<ArchRoofPart> AllRoofs( this ArchPlan plan, ArchKinds table = null ) => plan.Parts<ArchRoofPart>( table );
}