"BIM there, fixed that!"

"BIM there, fixed that!"

"BIM there, fixed that!"

"BIM there, fixed that!"

Cn3D Construction, a U.S. CAD company

"BIM there, fixed that!"

"BIM there, fixed that!"

"BIM there, fixed that!"

"BIM there, fixed that!"

"BIM there, fixed that!"

"BIM there, fixed that!"

​​​​​​LEVEL OF DEVELOPMENT (LOD) Cn3D/US CAD style

LOD from our perspective

For the most part we follow the BIMForum's LOD Specification. Kudos to this organization for putting this together every year and putting some roots down to help everyone understand the levels a model can become, and the purpose behind every stage.


At Cn3D/US CAD we've expanded on the LOD spec to define what you, our client, receives at various LOD's. You are more than welcome to pick and choose exactly how you want your model to come out, we just need to know before bid time. Our definitions of LOD 300, 350 and 400 are broken up between electrical, duct and pipe/plumbing. Happy scrolling.

US CAD ELECTRICAL LOD DEFINITIONS

Electrical LOD 300

  1. BIMForum interpretation:  The quantity, size, shape, location, and orientation of the element as designed can be measured directly from the model without referring to non-modeled information such as notes or dimension call-outs.  The project origin is defined and the element is located accurately with respect to the project origin.

  2. All elements modeled with the best matching items available in the Revit and Revit MEP default database

  3. 3D Model containing all needed information for A/E contract documents

  4. Little or no Architecture/Structure and MEPF coordination

  5. Shop Drawings will match the scale and orientation of the construction documents

  6. No hanger, penetration or block-out drawings provided unless added to the estimate

  7. Typical CD layout, lack of coordination- only taken to 80%

  8. Electrical conduit modeled 2" or greater (excluding insulation, lining or wrap) are modeled; or anything that is on a rack of three is modeled.

  9. None of the equipment is per submittal

  10. No conduit drawn, sometimes no cable tray is drawn

  11. No hangers


Electrical LOD 350

  1. BIMForum interpretation.  Parts necessary for coordination of the element with nearby or attached elements are modeled.  These parts will include such items as supports and connections.  The quantity, size, shape, location, and orientation of the element as designed can be measured directly from the model without referring to non-modeled information such as notes or dimension call-outs.

  2. All elements modeled with the best matching items available in the Revit and Revit MEP default database

  3. Coordinated with other trades to point of sign-off or other approval

  4. Shop Drawings will match the scale and orientation of the construction documents or subcontractor standards

  5. Penetration and sleeve drawings if requested at bid time

  6. Hanger Drawings

    1. Hangers coordinated

    2. Dimension unistrut hangers

    3. Hanger drawings are only given at 95% completion or greater

    4. No seismic bracing is modeled

  7. Electrical modeling includes conduit racks of 3 conduits or more and individual conduits 1.25” and greater, cable tray, panels, electrical gear needed for coordination, lights sized for coordination.

  8. All equipment is per approved submittal

  9. Conduit and cable tray drawn, per subcontractor input

  10. Clearances shown per NEMA and project specifications

  11. Hangers only on racks of 3 or more conduits and coordinated. No individual conduit hangers.

  12. Conduit rack coordinated to electrical rooms, but not to equipment

  13. Conduit is not labeled

  14. Only telecom (voice, data and video) main runs are modeled

  15. Does not include in-wall content or in-wall coordination

  16. Does not include ceiling mounted devices

  17. Does not include floor boxes


Electrical LOD 400

  1. BIMForum interpretation.  An LOD 400 element is modeled at sufficient detail and accuracy for fabrication of the represented component.  The quantity, size, shape, location, and orientation of the element as designed can be measured directly from the model without referring to non-modeled information such as notes or dimension call-outs.

  2. All elements modeled with the best matching items available in the Revit and Revit MEP default database

  3. Detailing, assembly, installation dimensions per subcontractor standards

  4. Specific parts, valves, fittings, materials, specifications, clean outs, etc.

  5. Primary fixtures are modeled with correct geometry per submittal information

  6. Coordinated with other trades to point of sign-off or other approval

  7. Shop Drawings will match the scale and orientation of the construction documents or subcontractor standards

  8. Penetration and sleeve drawings if requested at bid time

  9. Hanger Drawings

    1. Hangers coordinated

    2. Dimension unistrut hangers

    3. Hanger drawings are only given at 95% completion or greater

    4. No seismic bracing is modeled unless requested at bid time- layout must come from an engineer

  10. Electrical modeling includes conduit racks of 3 conduits or more and individual conduits 1.25” and greater, cable tray, panels, electrical gear needed for coordination, lights sized for coordination.

  11. All equipment is per approved submittal

  12. Conduit and cable tray drawn, per subcontractor input

  13. Clearances shown per NEMA and project specifications

  14. All conduit receives hangers added and coordinated

  15. Conduit rack coordinated to transformers, electrical panels and all gear

  16. Conduit runs are named with: From à To location

  17. Floor boxes are included if necessary

  18. Only telecom (voice, data and video) main runs are modeled

  19. Schedule(s) of parts are not included unless requested at bid time

  20. Ceiling mounted devices are not included unless requested at bid time

  21. In-wall content and coordination are not included unless requested at bid time

US CAD DUCT LOD DEFINITIONS

Duct LOD 300

  1. BIMForum interpretation:  The quantity, size, shape, location, and orientation of the element as designed can be measured directly from the model without referring to non-modeled information such as notes or dimension call-outs.  The project origin is defined and the element is located accurately with respect to the project origin.

  2. All elements modeled with the best matching items available in the Revit and Revit MEP default database

  3. 3D Model containing all needed information for A/E contract documents

  4. Little or no Architecture/Structure and MEPF coordination

  5. Shop Drawings will match the scale and orientation of the construction documents

  6. No hanger, penetration or block-out drawings provided unless added to the estimate

  7. Typical CD layout, lack of coordination- only taken to 80%

  8. None of the equipment is per submittal

  9. No lining or insulation shown

  10. Throat size inaccurate, transitions inaccurate, per engineer

  11. No hangers


Duct LOD 350

  1. BIMForum interpretation.  Parts necessary for coordination of the element with nearby or attached elements are modeled.  These parts will include such items as supports and connections.  The quantity, size, shape, location, and orientation of the element as designed can be measured directly from the model without referring to non-modeled information such as notes or dimension call-outs.

  2. All elements modeled with the best matching items available in the Revit and Revit MEP default database

  3. Coordinated with other trades to point of sign-off or other approval

  4. Shop Drawings will match the scale and orientation of the construction documents or subcontractor standards

  5. Penetration and sleeve drawings if requested at bid time

  6. Hanger Drawings

    1. Hangers coordinated

    2. Strap is used on duct up to 24"

    3. Unistrut is used on duct that is 24"-60"

    4. Above 60" is double strut

    5. Dimension unistrut hangers

    6. Hanger drawings are only given at 95% completion or greater

    7. No seismic bracing is modeled

  7. All of the duct work fittings will need to be modeled with true to field fittings.

  8. All equipment is per approved submittal

  9. Correct lining and insulation modeled

  10. Throat size and transitions correct per subcontractor standards

  11. Clearances shown per SMACNA and project specifications

  12. Strap is used on duct up to 24"

  13. Unistrut is used on duct that is 24"-60"

  14. Above 60" is double strut

  15. Transitions and fittings tagged on shop drawings

  16. Diffuser types, size and CFMs tagged on shop drawings

  17. Properly insulated or lined

  18. Duct fitting schedule provided upon request​


Duct LOD 400

  1. BIMForum interpretation.  An LOD 400 element is modeled at sufficient detail and accuracy for fabrication of the represented component.  The quantity, size, shape, location, and orientation of the element as designed can be measured directly from the model without referring to non-modeled information such as notes or dimension call-outs.

  2. All elements modeled with the best matching items available in the Revit and Revit MEP default database

  3. Detailing, assembly, installation dimensions per subcontractor standards

  4. Specific parts, valves, fittings, materials, specifications, clean outs, etc.

  5. Primary fixtures are modeled with correct geometry per submittal information

  6. Coordinated with other trades to point of sign-off or other approval

  7. Shop Drawings will match the scale and orientation of the construction documents or subcontractor standards

  8. Penetration and sleeve drawings if requested at bid time

  9. Hanger drawings

    1. Hangers coordinated

    2. Strap is used on duct up to 24"

    3. Unistrut is used on duct that is 24"-60"

    4. Above 60" is double strut

    5. Dimension unistrut hangers

    6. Hanger drawings are only given at 95% completion or greater

    7. No seismic bracing is modeled unless requested at bid time- layout must come from an engineer

  10. Fab Parts for Revit used if wanted (use your database or ours)

  11. All of the duct work fittings modeled with true to field fittings.

  12. All equipment is per approved submittal

  13. Correct lining and insulation modeled

  14. Throat size and transitions correct per shop standards

  15. Clearances shown per SMACNA and project specifications

  16. Transitions and fittings tagged on shop drawings

  17. Diffuser types, size and CFMs tagged on shop drawings

  18. Duct lengths split per client standards (included in reports)

  19. Includes schedule(s) of parts

  20. Duct fitting schedule provided upon request

  21. Shop Drawings: does not include part number or lengths identification (this is in the report)


US CAD PIPE & PLUMBING LOD DEFINITIONS

Pipe & Plumbing LOD 300

  1. BIMForum interpretation:  The quantity, size, shape, location, and orientation of the element as designed can be measured directly from the model without referring to non-modeled information such as notes or dimension call-outs.  The project origin is defined and the element is located accurately with respect to the project origin.

  2. All elements modeled with the best matching items available in the Revit and Revit MEP default database

  3. 3D Model containing all needed information for A/E contract documents

  4. Little or no Architecture/Structure and MEPF coordination

  5. Shop Drawings will match the scale and orientation of the construction documents

  6. No hanger, penetration or block-out drawings provided unless added to the estimate

  7. Typical CD layout, lack of coordination- only taken to 80%

  8. Piping modeled 2" or greater (excluding insulation, lining or wrap) are modeled; or anything that is on a rack of three is modeled.

  9. None of the equipment is per submittal

  10. Generic pipe fittings

  11. Inaccurate transition sizes

  12. No insulation

  13. No hangers


Pipe & Plumbing LOD 350

  1. BIMForum interpretation.  Parts necessary for coordination of the element with nearby or attached elements are modeled.  These parts will include such items as supports and connections.  The quantity, size, shape, location, and orientation of the element as designed can be measured directly from the model without referring to non-modeled information such as notes or dimension call-outs.

  2. All elements modeled with the best matching items available in the Revit and Revit MEP default database

  3. Coordinated with other trades to point of sign-off or other approval

  4. Shop Drawings will match the scale and orientation of the construction documents or subcontractor standards

  5. Penetration and sleeve drawings if requested at bid time

  6. Hanger Drawings

    1. Hangers for racks of 3 or more (no clevis hangers)

    2. Dimension unistrut hangers

    3. Hanger drawings are only given at 95% completion or greater

    4. No seismic bracing is modeled

  7. Piping will be modeled 1.25" or greater; or anything that is on a rack of three is modeled.

  8. All equipment is per approved submittal

  9. Fittings replaced with accurate sizes

  10. Slope added to DWV, steam and condensate per project specifications

  11. Clearances shown per ASME and project specifications

  12. Insulation added

  13. Does not include in-wall content or in-wall coordination


Pipe & Plumbing LOD 400

  1. BIMForum interpretation.  An LOD 400 element is modeled at sufficient detail and accuracy for fabrication of the represented component.  The quantity, size, shape, location, and orientation of the element as designed can be measured directly from the model without referring to non-modeled information such as notes or dimension call-outs.

  2. All elements modeled with the best matching items available in the Revit and Revit MEP default database

  3. Detailing, assembly, installation dimensions per subcontractor standards

  4. Specific parts, valves, fittings, materials, specifications, clean outs, etc.

  5. Primary fixtures are modeled with correct geometry per submittal information

  6. Coordinated with other trades to point of sign-off or other approval

  7. Shop Drawings will match the scale and orientation of the construction documents or subcontractor standards

  8. Penetration and sleeve drawings if requested at bid time

  9. Hanger Drawings

    1. Hangers for racks of 3 or more and clevis hangers included

    2. Dimension unistrut hangers

    3. Hanger drawings are only given at 95% completion or greater

    4. No seismic bracing is modeled unless requested at bid time- layout must come from an engineer

  10. All equipment is per approved submittal

  11. Fab Parts for Revit used if wanted (use your database or ours)

  12. Fittings replaced with accurate representations (size)

  13. Slope added to DWV, steam and condensate per project specifications

  14. Clearances shown per ASME and project specifications

  15. Insulation added

  16. Final equipment connections per submittals

  17. Adding ALL submittal data (thermometers, gauges, test ports, isolator pads, etc.)

  18. Spool map and spool drawings per subcontractor standards

  19. Includes schedule(s) of parts