效率与协作 · SKILL.md

ifcos-impl-mep

ifcos-impl-mep

【效率与协作】Use when modeling MEP (Mechanical, Electrical, Plumbing) systems in IFC -- HVAC, piping, electrical circuits, distribution elements, ports, and connections. Prevents the common mistake of not creating ports for flow connections between elements. Covers IfcSystem, IfcDistributionElement, flow segments, fittings, and MEP property sets. Keywords: MEP, H…

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IImpertio-Studio / Blender-Bonsai-ifcOpenshell-Sverchok-Claude-Skill-PackageMIT

技能说明

GitHub

name: ifcos-impl-mep description: > Use when modeling MEP (Mechanical, Electrical, Plumbing) systems in IFC -- HVAC, piping, electrical circuits, distribution elements, ports, and connections. Prevents the common mistake of not creating ports for flow connections between elements. Covers IfcSystem, IfcDistributionElement, flow segments, fittings, and MEP property sets. Keywords: MEP, HVAC, piping, electrical, IfcSystem, IfcDistributionElement, port, connection, flow segment, fitting, mechanical, plumbing, duct, ventilation, connect pipes. license: MIT compatibility: "Designed for Claude Code. Requires IfcOpenShell Python library." metadata: author: OpenAEC-Foundation version: "1.0"

MEP System Implementation Guide

Quick Reference

Critical Warnings

ALWAYS create ports on distribution elements BEFORE attempting to connect them. Elements without ports cannot participate in flow networks.
ALWAYS create at least two ports per segment element (one inlet, one outlet). Segments are flow-through elements.
NEVER connect two ports with the same flow direction. A SOURCE port MUST connect to a SINK port.
NEVER use IfcDistributionSystem in IFC2X3 models. Use ifc_class="IfcSystem" for IFC2X3 compatibility.
ALWAYS use ifcopenshell.api.run("system.add_system", ...) to create systems. NEVER use model.create_entity("IfcDistributionSystem") directly — it skips required relationship setup.
ALWAYS assign elements to a system AFTER creating port connections. The system is a logical grouping; ports define the physical topology.
NEVER assume system.remove_system deletes contained elements. It ONLY removes the system grouping; elements and their ports remain in the model.
ALWAYS use ifcopenshell.api.run("root.create_entity", ...) for MEP elements, not model.create_entity(). The API sets GlobalId, ownership, and validates predefined types.
ALWAYS pass products as a list to system.assign_system (v0.8+ convention).

Decision Tree: MEP Workflow

Creating an MEP system?
├── Step 1: What IFC schema version?
│   ├── IFC2X3 → Use ifc_class="IfcSystem" for add_system
│   └── IFC4 / IFC4X3 → Use ifc_class="IfcDistributionSystem" (default)
│
├── Step 2: Create the system
│   └── system.add_system → system.edit_system (set Name + PredefinedType)
│
├── Step 3: Create distribution elements
│   ├── Duct/Pipe/Cable? → IfcDuctSegment, IfcPipeSegment, IfcCableSegment
│   ├── Elbow/Tee/Junction? → IfcDuctFitting, IfcPipeFitting, IfcCableFitting
│   ├── Air terminal/Fixture? → IfcAirTerminal, IfcSanitaryTerminal
│   ├── Valve/Damper/Switch? → IfcValve, IfcDamper, IfcSwitchingDevice
│   ├── Pump/Fan? → IfcPump, IfcFan
│   ├── Boiler/Chiller? → IfcBoiler, IfcChiller
│   └── Tank/Vessel? → IfcTank
│
├── Step 4: Create ports on each element
│   └── system.add_port (per connection point)
│
├── Step 5: Connect ports between elements
│   └── system.connect_port (port1, port2, direction)
│
├── Step 6: Assign elements to system
│   └── system.assign_system (products=[...], system=system)
│
├── Step 7: Assign flow controls (optional)
│   └── system.assign_flow_control (damper→duct, valve→pipe)
│
└── Step 8: Add properties and placement
    ├── pset.add_pset / pset.edit_pset (MEP property sets)
    └── geometry (placement, representation)

Decision Tree: Which Distribution Element Class

What type of MEP element?
├── Carries flow (segments)?
│   ├── Air/gas → IfcDuctSegment
│   ├── Liquid → IfcPipeSegment
│   ├── Electrical → IfcCableSegment
│   └── Cable carrier → IfcCableCarrierSegment
│
├── Changes direction/splits (fittings)?
│   ├── Air/gas → IfcDuctFitting
│   ├── Liquid → IfcPipeFitting
│   ├── Electrical → IfcCableFitting
│   └── Cable carrier → IfcCableCarrierFitting
│
├── End point (terminals)?
│   ├── Air supply/return → IfcAirTerminal
│   ├── Plumbing fixture → IfcSanitaryTerminal
│   ├── Electrical outlet → IfcOutlet
│   ├── Light fixture → IfcLightFixture
│   ├── Fire sprinkler → IfcFireSuppressionTerminal
│   └── Communication jack → IfcCommunicationsAppliance
│
├── Controls flow (controllers)?
│   ├── Airflow → IfcDamper
│   ├── Liquid flow → IfcValve
│   ├── Electrical → IfcSwitchingDevice / IfcProtectiveDevice
│   └── Flow meter → IfcFlowMeter
│
├── Moves medium (movers)?
│   ├── Air → IfcFan
│   ├── Liquid → IfcPump
│   └── Gas → IfcCompressor
│
├── Converts energy?
│   ├── Heating → IfcBoiler
│   ├── Cooling → IfcChiller
│   ├── Heat exchange → IfcHeatExchanger
│   ├── Cooling tower → IfcCoolingTower
│   ├── Air handling → IfcAirToAirHeatRecovery / IfcUnitaryEquipment
│   └── Electrical → IfcTransformer / IfcElectricGenerator
│
├── Stores medium?
│   ├── Liquid → IfcTank
│   └── Electrical → IfcElectricFlowStorageDevice
│
├── Treats medium?
│   ├── Air filter → IfcFilter
│   └── Grease/oil trap → IfcInterceptor
│
└── Senses/monitors (control elements)?
    ├── Temperature → IfcSensor (TEMPERATURESENSOR)
    ├── Pressure → IfcSensor (PRESSURESENSOR)
    ├── Flow rate → IfcSensor (FLOWSENSOR)
    ├── Smoke → IfcSensor (SMOKESENSOR)
    └── Actuator → IfcActuator

Essential Patterns

Pattern 1: Complete HVAC System (IFC4)

# IFC4 / IFC4X3
import ifcopenshell
import ifcopenshell.api

model = ifcopenshell.api.run("project.create_file", version="IFC4")

# Bootstrap (project, units, contexts, spatial hierarchy)
project = ifcopenshell.api.run("root.create_entity", model,
    ifc_class="IfcProject", name="MEP Project")
ifcopenshell.api.run("unit.assign_unit", model)
model3d = ifcopenshell.api.run("context.add_context", model, context_type="Model")
body = ifcopenshell.api.run("context.add_context", model,
    context_type="Model", context_identifier="Body",
    target_view="MODEL_VIEW", parent=model3d)
site = ifcopenshell.api.run("root.create_entity", model,
    ifc_class="IfcSite", name="Site")
building = ifcopenshell.api.run("root.create_entity", model,
    ifc_class="IfcBuilding", name="Building A")
storey = ifcopenshell.api.run("root.create_entity", model,
    ifc_class="IfcBuildingStorey", name="Level 1")
ifcopenshell.api.run("aggregate.assign_object", model,
    products=[site], relating_object=project)
ifcopenshell.api.run("aggregate.assign_object", model,
    products=[building], relating_object=site)
ifcopenshell.api.run("aggregate.assign_object", model,
    products=[storey], relating_object=building)

# Step 1: Create distribution system
hvac = ifcopenshell.api.run("system.add_system", model,
    ifc_class="IfcDistributionSystem")
ifcopenshell.api.run("system.edit_system", model,
    system=hvac,
    attributes={"Name": "Supply Air System", "PredefinedType": "VENTILATION"})

# Step 2: Create elements
ahu = ifcopenshell.api.run("root.create_entity", model,
    ifc_class="IfcUnitaryEquipment", name="AHU-01")
duct1 = ifcopenshell.api.run("root.create_entity", model,
    ifc_class="IfcDuctSegment", name="SD-01")
duct2 = ifcopenshell.api.run("root.create_entity", model,
    ifc_class="IfcDuctSegment", name="SD-02")
terminal = ifcopenshell.api.run("root.create_entity", model,
    ifc_class="IfcAirTerminal", name="AT-01")

# Step 3: Place in spatial structure
ifcopenshell.api.run("spatial.assign_container", model,
    products=[ahu, duct1, duct2, terminal], relating_structure=storey)

# Step 4: Create ports (inlet + outlet per segment)
ahu_out = ifcopenshell.api.run("system.add_port", model, element=ahu)
d1_in = ifcopenshell.api.run("system.add_port", model, element=duct1)
d1_out = ifcopenshell.api.run("system.add_port", model, element=duct1)
d2_in = ifcopenshell.api.run("system.add_port", model, element=duct2)
d2_out = ifcopenshell.api.run("system.add_port", model, element=duct2)
term_in = ifcopenshell.api.run("system.add_port", model, element=terminal)

# Step 5: Connect ports (AHU → Duct1 → Duct2 → Terminal)
ifcopenshell.api.run("system.connect_port", model,
    port1=ahu_out, port2=d1_in, direction="SOURCE")
ifcopenshell.api.run("system.connect_port", model,
    port1=d1_out, port2=d2_in, direction="SOURCE")
ifcopenshell.api.run("system.connect_port", model,
    port1=d2_out, port2=term_in, direction="SOURCE")

# Step 6: Assign all elements to the system
ifcopenshell.api.run("system.assign_system", model,
    products=[ahu, duct1, duct2, terminal], system=hvac)

Pattern 2: Piping Network with Fittings

# IFC4 / IFC4X3: requires completed bootstrap
# Create plumbing system
plumbing = ifcopenshell.api.run("system.add_system", model,
    ifc_class="IfcDistributionSystem")
ifcopenshell.api.run("system.edit_system", model,
    system=plumbing,
    attributes={"Name": "Hot Water Supply", "PredefinedType": "DOMESTICHOTWATER"})

# Create pipe elements
pipe1 = ifcopenshell.api.run("root.create_entity", model,
    ifc_class="IfcPipeSegment", name="HWS-P01")
elbow = ifcopenshell.api.run("root.create_entity", model,
    ifc_class="IfcPipeFitting", name="HWS-E01")
pipe2 = ifcopenshell.api.run("root.create_entity", model,
    ifc_class="IfcPipeSegment", name="HWS-P02")
valve = ifcopenshell.api.run("root.create_entity", model,
    ifc_class="IfcValve", name="HWS-V01")

# Ports: pipes need 2, fittings need 2+, terminals need 1
p1_in = ifcopenshell.api.run("system.add_port", model, element=pipe1)
p1_out = ifcopenshell.api.run("system.add_port", model, element=pipe1)
elb_in = ifcopenshell.api.run("system.add_port", model, element=elbow)
elb_out = ifcopenshell.api.run("system.add_port", model, element=elbow)
p2_in = ifcopenshell.api.run("system.add_port", model, element=pipe2)
p2_out = ifcopenshell.api.run("system.add_port", model, element=pipe2)

# Connect: Pipe1 → Elbow → Pipe2
ifcopenshell.api.run("system.connect_port", model,
    port1=p1_out, port2=elb_in, direction="SOURCE")
ifcopenshell.api.run("system.connect_port", model,
    port1=elb_out, port2=p2_in, direction="SOURCE")

# Assign flow control (valve controls pipe)
ifcopenshell.api.run("system.assign_flow_control", model,
    relating_flow_element=pipe1, related_flow_control=valve)

# Assign to system
ifcopenshell.api.run("system.assign_system", model,
    products=[pipe1, elbow, pipe2, valve], system=plumbing)

Pattern 3: Tee Fitting (3 Ports)

# IFC4 / IFC4X3
tee = ifcopenshell.api.run("root.create_entity", model,
    ifc_class="IfcPipeFitting", name="HWS-T01")

# Tee fittings have 3 ports: inlet, outlet-main, outlet-branch
tee_in = ifcopenshell.api.run("system.add_port", model, element=tee)
tee_out1 = ifcopenshell.api.run("system.add_port", model, element=tee)
tee_out2 = ifcopenshell.api.run("system.add_port", model, element=tee)

# Connect: upstream pipe → tee inlet
# tee outlet1 → downstream main
# tee outlet2 → downstream branch
ifcopenshell.api.run("system.connect_port", model,
    port1=upstream_pipe_out, port2=tee_in, direction="SOURCE")
ifcopenshell.api.run("system.connect_port", model,
    port1=tee_out1, port2=main_pipe_in, direction="SOURCE")
ifcopenshell.api.run("system.connect_port", model,
    port1=tee_out2, port2=branch_pipe_in, direction="SOURCE")

Pattern 4: IFC2X3 System (Backward Compatible)

# IFC2X3: use IfcSystem instead of IfcDistributionSystem
model = ifcopenshell.api.run("project.create_file", version="IFC2X3")
# ... bootstrap ...

system = ifcopenshell.api.run("system.add_system", model,
    ifc_class="IfcSystem")  # REQUIRED for IFC2X3
ifcopenshell.api.run("system.edit_system", model,
    system=system,
    attributes={"Name": "Heating System"})
# NOTE: PredefinedType is NOT available on IfcSystem in IFC2X3.
# Use ObjectType attribute for classification instead.
ifcopenshell.api.run("attribute.edit_attributes", model,
    product=system,
    attributes={"ObjectType": "HEATING"})

Distribution System Types (IFC4 / IFC4X3)

Set via PredefinedType attribute on IfcDistributionSystem:

PredefinedType	Domain	Description
`VENTILATION`	HVAC	Supply/return/exhaust air systems
`HEATING`	HVAC	Hot water heating, radiator circuits
`COOLING`	HVAC	Chilled water, refrigerant loops
`AIRCONDITIONING`	HVAC	Combined heating/cooling air systems
`EXHAUST`	HVAC	Kitchen/fume exhaust systems
`DOMESTICHOTWATER`	Plumbing	Hot water supply
`DOMESTICCOLDWATER`	Plumbing	Cold water supply
`DRAINAGE`	Plumbing	Gravity drainage, waste water
`WASTEWATER`	Plumbing	Waste water systems
`STORMWATER`	Plumbing	Rainwater drainage
`SEWAGE`	Plumbing	Sewer connections
`RAINWATER`	Plumbing	Rainwater collection
`ELECTRICAL`	Electrical	Power distribution
`LIGHTING`	Electrical	Lighting circuits
`POWERGENERATION`	Electrical	On-site power generation
`LIGHTNINGPROTECTION`	Electrical	Lightning protection systems
`EARTHING`	Electrical	Grounding/earthing
`FIREPROTECTION`	Fire	Sprinklers, fire suppression
`SECURITY`	Security	Access control, CCTV
`COMMUNICATION`	Comms	Data/telephone networks
`DATA`	Comms	Data networks
`TV`	Comms	Television distribution
`SIGNAL`	Controls	Signal/control systems
`CONTROL`	Controls	Building automation
`GAS`	Fuel	Natural gas distribution
`FUEL`	Fuel	Fuel supply systems
`COMPRESSEDAIR`	Pneumatic	Compressed air distribution
`VACUUM`	Pneumatic	Vacuum systems
`REFRIGERATION`	HVAC	Refrigeration systems
`CHILLEDWATER`	HVAC	Chilled water distribution
`CONDENSERWATER`	HVAC	Condenser water loops
`CHEMICAL`	Process	Chemical distribution
`DISPOSAL`	Waste	Waste disposal systems
`HAZARDOUS`	Safety	Hazardous material systems
`CONVEYING`	Transport	Material conveying
`USERDEFINED`	Custom	Set ObjectType attribute
`NOTDEFINED`	Default	Unspecified

Port Flow Directions

Direction	Meaning	When to Use
`SOURCE`	Flow exits through this port	Outlet ports, downstream direction
`SINK`	Flow enters through this port	Inlet ports, upstream direction
`SOURCEANDSINK`	Bidirectional flow	Reversible systems, heat exchangers
`NOTDEFINED`	Direction not specified	When flow direction is unknown

Rule: When connecting two ports, direction on connect_port describes the relationship from port1's perspective. If port1 is a SOURCE, flow goes from port1 to port2.

System Traversal (ifcopenshell.util.system)

# IFC4 / IFC4X3
import ifcopenshell.util.system

# Get all elements in a system
elements = ifcopenshell.util.system.get_system_elements(hvac)

# Get all systems an element belongs to
systems = ifcopenshell.util.system.get_element_systems(duct1)

# Get ports on an element (optionally filter by direction)
all_ports = ifcopenshell.util.system.get_ports(duct1)
outlets = ifcopenshell.util.system.get_ports(duct1, flow_direction="SOURCE")
inlets = ifcopenshell.util.system.get_ports(duct1, flow_direction="SINK")

# Traverse connections: downstream / upstream
downstream = ifcopenshell.util.system.get_connected_to(duct1)
upstream = ifcopenshell.util.system.get_connected_from(duct1)

# Get element that owns a port
owner = ifcopenshell.util.system.get_port_element(d1_out)

# Get port connected to a given port
partner = ifcopenshell.util.system.get_connected_port(d1_out)

MEP Property Sets

Standard Property Sets for Distribution Elements

# IFC4 / IFC4X3: Add MEP-specific properties
# Duct segment properties
pset = ifcopenshell.api.run("pset.add_pset", model,
    product=duct1, name="Pset_DuctSegmentTypeCommon")
ifcopenshell.api.run("pset.edit_pset", model, pset=pset, properties={
    "NominalDiameter": 0.315,      # meters
    "InnerDiameter": 0.313,
    "OuterDiameter": 0.315,
    "Length": 3.0,
})

# Pipe segment properties
pset_pipe = ifcopenshell.api.run("pset.add_pset", model,
    product=pipe1, name="Pset_PipeSegmentTypeCommon")
ifcopenshell.api.run("pset.edit_pset", model, pset=pset_pipe, properties={
    "NominalDiameter": 0.025,
    "InnerDiameter": 0.021,
    "OuterDiameter": 0.025,
    "WorkingPressure": 600000.0,    # Pascals
    "FlowRateRange": "0.1 - 0.5",  # m3/s
})

# Quantity set for a duct
qto = ifcopenshell.api.run("pset.add_qto", model,
    product=duct1, name="Qto_DuctSegmentBaseQuantities")
ifcopenshell.api.run("pset.edit_qto", model, qto=qto, properties={
    "Length": 3.0,
    "GrossCrossSectionArea": 0.078,
    "OuterSurfaceArea": 2.97,
})

Common MEP Pset Names

Element Type	Property Set	Key Properties
Duct segments	`Pset_DuctSegmentTypeCommon`	NominalDiameter, Length
Pipe segments	`Pset_PipeSegmentTypeCommon`	NominalDiameter, WorkingPressure
Air terminals	`Pset_AirTerminalTypeCommon`	AirFlowRateRange, NominalAirFlowRate
Valves	`Pset_ValveTypeCommon`	ValvePattern, WorkingPressure
Pumps	`Pset_PumpTypeCommon`	FlowRateRange, NominalRotationSpeed
Fans	`Pset_FanTypeCommon`	NominalAirFlowRate, NominalTotalPressure
Boilers	`Pset_BoilerTypeCommon`	NominalEnergyConsumption, WaterTemperatureRange

Version Differences

Feature	IFC2X3	IFC4	IFC4X3
System class	`IfcSystem`	`IfcDistributionSystem`	`IfcDistributionSystem`
PredefinedType on system	Not available	Full enum (37 values)	Full enum + additions
Building system	Not available	`IfcBuildingSystem`	`IfcBuildingSystem`
Port nesting	`IfcRelNests`	`IfcRelNests`	`IfcRelNests`
Port connection	`IfcRelConnectsPorts`	`IfcRelConnectsPorts`	`IfcRelConnectsPorts`
Flow direction enum	Same	Same	Same

Version-Safe Pattern

# Detect schema and choose correct system class
schema = model.schema
if schema == "IFC2X3":
    system = ifcopenshell.api.run("system.add_system", model,
        ifc_class="IfcSystem")
else:
    system = ifcopenshell.api.run("system.add_system", model,
        ifc_class="IfcDistributionSystem")

Dependency

This skill depends on:

ifcos-syntax-api for api.run() invocation patterns, module table, and parameter conventions
ifcos-syntax-fileio for file creation, writing, and transaction management

Reference Links

API Method Signatures -- Complete signatures for all 12 system API functions
Working Code Examples -- End-to-end MEP system examples
Anti-Patterns -- Common MEP modeling mistakes and how to avoid them

Official Sources

MAKE IT PART OF YOUR WORKFLOW

安装技能

TERMINAL

npx skills add Impertio-Studio/Blender-Bonsai-ifcOpenshell-Sverchok-Claude-Skill-Package --skill ifcos-impl-mep

复制命令到本地终端执行；安装前请先审查源代码和许可证。

完整包范围

Complete original skill directory with source license/notice; external tools, shared sibling skills and APIs remain external.

ZIP · 完整技能目录，含资源与许可证

SKILL.md · 仅技能说明原文

仓库 Star: 41
许可证: MIT
版本 / 分支: main · 1cad8966
仓库更新时间: 2026-07-08

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源代码