Considerations of BIM/Model Setup

Formerly titled: "Ten Objectives of Model Origin and Setup"

In this detailed article, we study what are all the items which need to be taken into consideration with establishing a BIM Model.


Last Updated 06/06/2018. This Article is regularly updated to ensure its correctness.

A:- Premise:
A.1.1:- The below premises of this article have been applied where possible within the "BIMFix Framework for Shared Model Establishment" which can be downloaded for free from the BIMfix website here.

A.1.1:- Considerations: When it comes to the BIM model project setup, origin selection and the coordinate system; BIM Models have many considerations to take into account. 

 A.1.2:- This includes:
  1.  Limited survey data available at project kick-off,
  2. World Geodetic Datum / System (Real World Coordinates),
  3. Limitations of Computer 64 Bit precision,
  4. Different project discipline member needs,
  5. Different BIM deliverable needs,
  6. Scalable within projects sizes and types,
  7. Building relocation management,
  8. Allocation of responsibility and risk mitigation,
  9. Allowance for human error, and follow-up resolution,
  10. Work within international standards,
  11. Surveying accuracy,
  12. IFC file model origin,
  13. BIM authoring tools translocation capabilities,
A.1.3:- Are you planning to Fail? Do your project model establishment processes take all the above items into account? If not; you are putting the project BIM and Documentation Outcomes at risk, or opening up the delivery team to fail. There is a lot of truth in the saying;

                                          "Failing to plan is planning to fail,"


A.1.4:- The Past: Over the past two decades, 3D models are commonly circulated between project teams to enhance coordination, communication and meet deliverables. When dealing with 2D (CAD files & Paper), very few drafters were concerned with their CAD file accommodating for other project participant workflows. Other participants drawings had the sole purpose of providing backgrounds or visual coordination underlay references.

A.1.5:- Today: However now; there are many potential uses of models:

  1. The use of neutral openBIM formats, such as IFC and COBie, is becoming central to project coordination and delivery.
  2. Components from one discipline can be hosted directly on another disciplines element,
  3. Identical components across discipline models may have spatial monitoring engaged,
  4. Consultants may be obtaining Geodetic Datum coordinates from the Design Leads model,
  5. Components data may be annotated, scheduled, or graphically filtered across discipline models,
  6. Components of the model can be directly used for element set-out (e.g. Trimble robotic total station),
  7. Models are becoming the center of team communication, with file formats such as BCF (BIM Collaboration Format). This may need to work between relevant applications involved.
A.1.6:- Bottom Line: There is greater use of models across multiple deliverables and they are expected to seamlessly integrate between disciplines and applications.
A.1.7:- Impact: An inappropriate model establishment will have a direct impact on project teams. Let’s elaborate on the above list and understand the challenges and goals.

 A.1.8:- Scope: Australia is given as an example in this article, however, similar principles are applicable in most countries around the world. Please note, naming and terminology may change per country.


1. Limited survey data available at project kick-off
1,0.1:- It is rare to have a comprehensive site survey at project kick-off, or even concept/sketch design stage. Ideally, a CAD survey is available from the Land Surveyor, about 8 weeks before the end of Sketch Design.

1.0.2:- Flexibility: On the first few days of building modeling conception, datum heights and spatial coordinates are not a high priority on most projects. There are, of course, exceptions. Designers need to evolve the design principles with limited site information. Model users may not understand the potential consequences of a bad project set-up, and thus, a simple, user-friendly approach (plan) is likely to succeed.


2. World Geodetic System (Real World Coordinates)
2.1:- Geodetic Datum
2.1.1: - Every Building or structure will have a location that is relative to the World Geodetic Datum / System. Australia’s geodetic datum happens to be the Geodetic Datum of Australia (GDA), and other countries will have their own Geodetic Datum, Surveyors and Civil disciplines will align with.
Geodetic Datum of Australia (GDA) coordinate system fits into the global coordinate system. It came into use in 1994 (updated 2017 - GDA2020) and is compatible with the Global Positioning System (GPS). It includes Grid coordinates (Universal Transverse Mercator (UTM), using the GRS80 ellipsoid); called Map Grid of Australia (MGA). Note: This replaces the former grid system Australian Map Grid (AMG).
Universal Transverse Mercator (UTM), was first developed by the United States Army Corps of Engineers.



                        Above image: Map Grid of Australia 1994
2.1.2: - Other Regions: Most countries have their own Universal Transverse Mercator (UTM) Grid using a WGS84 based system.:



2.1.3: - Overview: MGA fits within the global “Longitude” grid (vertical) and is 6⁰ of separation (giving 60 Zones). It starts at the International Date Line and works anti-clockwise around the earth. Each grid sector is allocated a Zone number sequentially. Australia is between Zone 49 (West W.A) and Zone 56 (East N.S.W. / QLD.). It uses the Cartesian coordinate system in a positive X, Y (Easting’s and Northing’s) to locate a point/position. A helpful converter from (Universal Transverse Mercator (UTM) Coordinates to Geographic (latitude, longitude) coordinate system: AWSM website.

2.1.4: - UTM Origin: The point of origin of each (Universal Transverse Mercator (UTM) zone is the intersection of the equator and the zone's central meridian. For the Southern Hemisphere in order to maintain positive values, the origin is measured 10,000KM south (down) of the Equator line (very close to the South-Pole). Also, to avoid negative eastings numbers, the central meridian of each zone is defined to coincide with 500,000 meters East. All coordinates are in the IS Units of meters.

 Location examples (approximate):

      Melbourne    MGA Zone 55    E 320,000 (Easting)      N 5,800,000 (Northing)
      Sydney         MGA Zone 56    E 330,000 (Easting)      N 6,250,000 (Northing)


                Above image: MGA (Map Grid of Australia) Zone origins - 500,000m West of the Central Meridian.

2.1.5:-  UTM Projection: UTM (Universal Transverse Mercator) represents ellipsoidal positions (latitude & longitude) as Grid coordinates (Easting and Northing) on a cylindrical surface, resulting in a number of zones. Uniform scale factor, false origins, and zone size and numbering have been adopted for the Universal Transverse Mercator Projection.

Image above – concept of Universal Mercator and Universal Transverse Mercator system – I.e. the attempt to flatten an Oblate Spheroid (the Earth) onto a flat surface. 


2.1.6: - UTM Scaling: Typically, World Maps use the (Universal Transverse Mercator (UTM), however, Map Grid of Australia maps use the Transverse Mercator system enabling less distortion in a North / South direction. There is an East / West distortion and it can be a Scale Factor varying from 0.9996 (Point A) and 1.00071 (Point C) as shown in the below sectional diagram.

Above diagram: Extract from The Map Grid of Australia 1994, A Simplified Computational Manual,  showing the Scale Factor will vary with the distance of the survey from the Central Meridian allowing for the East-West curvature of the Earth. 

2.1.7:- UTM Scaling Calculator: The Australian Government provides a free to use Calculator, which computes the scale factor (Point Scale) East-West deviation. Thus a Map Grid of Australia (MGA) survey with an Eastings of 510,200 (Close to the Central Meridian), as per the above calculator, will have a Point Scale of 0.99960128. Thus; 100 meters measured East-West in the CAD drawing will be in fact 100/0.99960128 = 100.040 meters on site. About +40mm out.

2.1.8:- Local Grids: Some local areas are a sub-section of MGA. Perth projects often work to Perth Coastal Grid (PCG). These smaller local grids allow for greater accuracy as they reduce some of the unfolding deviations which occur within the Universal Transverse Mercator (UTM). The bottom paragraph of this link provides guidance when working on large linear projects to minimize distortion.

 2.1.9:- Continents on the Move: The Earth's tectonic plates are in constant movement. It's very small, but they are still moving. All Geodetic Datums / Systems will have an associated point in time (Year) that it relates to. GDA2020, is the predicted location of the Australian continent on the 1st of January in 2020. Thus every Survey should contain the full datum information.

Above: The difference between GDA94 and GDA2020 coordinates is primarily due to

plate tectonic. (from: Geocentric Datum of Australia 2020 Technical Manual)


Above: Conformal (green) and distortion (red; high reliability) components of the transformation grids (from: Geocentric Datum of Australia 2020 Technical Manual)

2.2:- Elevation (Altitude or Height Datum)
2.2.1:- The “Z” coordinates (Elevation), Height Datum is used (For Australia: Australian Height Datum / AHD). In Australia, this is the mean sea level (Geoid) for 1966-1968 and was assigned a value of 0.000m with the surveying of 30 stations around Australia. All Australian surveys refer to AHD, and again the units are in meters.

 2.2.2:- Elevation Scaling: Please also note the height above mean sea level will also affect the output scale factor.

Above diagram: Shows, as the Elevation increases the Ground Distance increases vs. the Grid Distance. 
2.3:- Building Set-out (Layout)
2.3.1:- When annotating the set-out of a standalone commercial building, it is common to give Easting and Northing for the primary building set-out Grid (See Figure A.1 image below - Section 10). and the Height Datum elevation for each floor level.

2.3.2:- Coordinate Coordination: Civil Engineers, Land Surveyors, Transport Engineers all work to this official coordinate system, and it is an imperative any building information exchange integrate with them.
3. Limitations of Computer 64 Bit precision
3.1.1:- The above mentioned Geodetic (Universal Transverse Mercator (UTM) coordinates can become very large:
             Example:
             6,000,000 m      -        i.e 7 Figures before the decimal point, or
             6,000,000,000 mm -  i.e 10 Figures before the decimal point. 

 3.1.2:- How computers store numbers: Most software applications (including CAD applications and MS Excel) have limitations on how large numbers are stored (.i.e.: 64 Bit precision. CAD applications have stored coordinate figures in a 64 Bit precision since the early-1980's). These include the number of calculated figures they can effectively work with, due to Floating Point Precision engaged via the IEEE 754 Standard. What this means; when we get to the 15th and 16th figures of coordinates, the computer starts to produce rounding errors (see example below). 

3.1.3:- Resulting errors: To achieve the required functionality, ideally, 7 figures of precision are desired after the decimal point before the rounding error starts. Thus, If we have more than 8 figures, before the decimal point, we start to produce numerical/graphical errors, such as:

  1. radial arcs and tangential lines won't trim or display correctly, 
  2. graphical or view rendering errors (see image below),
  3. flickering/jumping items when orbiting/moving in 3D Open GL view,
  4. distortion/jumping when zooming in a long way 2D,
  5. lines may appear to flicker/jump on selection, 
  6. hatches won't display/print correctly,
  7. drawings disappearing or displaying as empty on layouts/viewports,
  8. renders are missing lights or objects,

3.1.4:- Sample (Universal Transverse Mercator (UTM) Coordinate for the Adelaide Convention Center:

             Coordinate Northing:              N  6,133,104.488,756,17 m
             Computer reads it as:                 6.13310448875616956502199172974E6
             
Computer 64 Bit Binary Format:
            Above: the figure shows the floating point rounding issue.

3.1.5:- Coding Units: Also, consider some US CAD Building applications (e.g. Autodesk Revit) are hardcoded in decimal feet, and changing the project unit settings may not change how the coordinate figures are stored. 

3.1.6:- Example Error: With all of the above, this is one reason land surveyors work in meters. The software is too unpredictable if they worked in millimeters. 
Thus, Building Design and Construction teams who want to work in millimeters must use a known (Easting and Northing identified) "Local" datum origin point.
Above:  Example of importing a Civil model (Sewage Manhole drainage system) from an IFC file format into Autodesk Revit, with the "Y" (Northing) value 360,000,000mm away from the origin. The round manhole polygon distortion is very obvious.
3.2:- Software references of the above problem:

3.2.1:- Autodesk AutoCAD:
3.2.2:- Autodesk Revit:
3.2.3:- Bentley:
3.2.4:- Graphisoft ArchiCAD:
3.2.5:- Microsoft Excel:
3.2.6:- Vectorworks:
3.2.7:- Trimble Sketchup:
3.2.8:- Trimble Tekla:
3.2.9:-  McNeel Rhino:
4. Different project discipline needs
4.1.1:- Most building projects can be split up into two camps; those dealing with the site infrastructure or civil works, and those dealing with the building itself. 

4.1.2:- Standard unit of length: The Meter was created in the early 1790's as one ten-millionth of the distance from the equator to the North Pole - French Academy of Sciences. That is; it was created by measuring a distance over land. 

 4.1.3:- Site Disciplines: All site related geodetic references ((Universal Transverse Mercator (UTM), & Height Datums) are in meters (meters are the SI Base Unit). As these disciplines are engaging large dimensional figures, it makes a lot of sense to work in meters. 

4.1.4:- Building Disciplines: However, within the Building and Fabrication disciplines, component set-outs and measurements are in millimeters.

 4.1.5:- Typical Discipline Split:

Site Disciplines: 
(length units meters)
Building Disciplines: 
(length units millimeters)
Land Surveyors
Architects and Interior Designers
Civil Engineers
Structural Engineers
GIS (Geographic Information System) Consultants
Building Services Engineers
Transport Engineers
Building Surveyor / BCA Consultants

Façade Engineers

Acoustics Engineers

Other building specialist consultants

Building Component fabrication modelers

NOTE: Landscape Architects often may prefer to work in millimeters and thus must work off the local site origin.

4.1.6:- Acknowledgement: As disciplines use different base units (meters/millimeters), an integrated workflow allowing for a coordinate data exchange needs to be established between project participants.


5. Different BIM deliverable needs
5.1.1:- When looking at the available BIM goals, many project team members will require a different approach to model coordinates and origins. Some examples;
  • 5.1.2:- Master Planning: When master planning a campus site, it may include GIS data working to Geodetic Coordinate Systems, multiple buildings, and staging strategies.
  • 5.1.3:- Clash Detection: 95% of Clash detection on building projects takes place within the building itself (this will be different on infrastructure projects). On a commercial Building construction project, the site clash detection is often minimum. Building relocations during design stages should not temporally hold-up the Clash Detection process. Clash Detection may also include fabrication model authoring applications which may not support Geodetic Coordinate Systems.
    Communication of Clash detection via (BCF) may require two-way communication. BCF files generally require identical model (hardcoded) origins between the applications in use.
  • 5.1.4:- Sustainability Evaluation: When defining the rating scheme used to check the model, (e.g. Green Star or LEED), the building orientation to true north, longitude, and latitude position, are transferred into the analysis application often via the model.
  • 5.1.5:- Positive and Small Coordinates: Some analysis applications require the geometry to be close to the origin and for all geometry to be positive figures. This is to minimize and simplify the computations. It will result in the Model origin being in the bottom right of the model. 
  • 5.1.6:- Software restrictions: As mentioned above, projects will have fabrication software unable to work with (Universal Transverse Mercator (UTM), coordinates, and there will also be some Civil consultants which are required to work to UTM coordinates.
5.1.6:- Acknowledgement: Thus, it is necessary for the approach to work with multiple units and origin points.



 6. Scalable within projects sizes and types
6.1.1:- Whatever approach and process are engaged, it needs to be scalable. That is, to work with:
  1. a single green / brown field site building,
  2. a multi-building campus environment, all buildings unique,
  3. a multi-building campus environment, with multiple building units (modules),
  4. a multi-campus project, with multiple building units (modules) across different campuses,
  5. a large single building, comprised of multiple discipline sub-models (due to file size, or multiple production centers),
  6. a project containing existing conditions, staging, and/or building extensions.
6.1.2:- Single Process: The goal is to have one overall simple workflow strategery, that works for a simple project, and only with minor tweaks works on large and complex projects.

7. Building relocation management
7.1.1:- From building design kick off, up until foundation concrete pouring, a building design relocation can occur. A relocation may be due to new data the designer have to integrate. Building movements can occur in any of the X, Y, Z and rotation values. Even if the building takes up 100% of the site, it may still move in the “Z” direction.

7.1.2:- Relocation effect: If not planned and managed appropriately; building relocations can have substantial adverse effects on project teams. Potentially adding weeks of documentation re-work for parties affected.

7.1.3:- Risk: Failure to address building relocations may open up liability to parties involved.

8. Allocation of responsibility and risk mitigation
8.1.1:- When it comes to “most” building projects (Infrastructure projects are an exception), the Design Lead is responsible for documenting where the building is located and set-out (layout) on the site. The Design Lead will determine this off a site survey provided during the early design stage by the Land Surveyor.

8.1.2:- Responsibility: As the design evolves, and the design location of the building updates, it is up to the Design Lead to take responsibility for relocation change and adequately communicate it to all relevant parties. All necessary processes must be established to eliminate other design consultants or contractors being requested to manually move their models or enter coordinates figures to align with the Design Lead's model. This is an unnecessary risk. 
If no processes and checking systems are in place, and parties get it wrong and costs are incurred, is the Design Lead going to reimburse them?


 9. Allowance for human error, and follow-up resolution
9.1.1:- No matter how good a process is, human error is often the weakest link. Thus, the overall workflow should take on board the following:
  1. A protection system in place, to avoid users accidentally moving linked models
  2. An audit at each deliverable stage to pick up coordinate/origin errors
  3. A backup coordinates reference system, to help in resolving any errors (Site Map Grid)
  4. If all fails a reset option, which will have minimum effect on other parties
10. Work within international standards
10.1.1:- There are not many specific standards in regard to site set-up/establishment, so when there is one, it’s worth adhering to it where possible. BS 1192:2007+A2:2016 - Collaborative production of architectural, engineering and construction information – Code of practice has a specific section on-site Coordinate establishment. The relative section is Annex A (normative); Project space statement. This section identifies the establishment of a site map grid (engaging Easting’s and Northing’s map grids). It suggests a location for a project site local origin (site grid origin), and the identification of at least two building grid intersection coordinates and rotation. 
Above:  Figure A.1 Geodetic referencing from BS 1192:2007+A2:2016.

10.1.2:- This approach is very robust, and it also can be used to facilitate item “9” above. BS 1192:2007 is a requirement of UK BIM Level 1 & 2.


10.1.3:- Other relevant Project Establishment and Building Coordinate Standards:

  1. AEC (UK) BIM Protocol For Autodesk® Revit® v2.0 - Sections 6.3.1, 7.4
  2. AEC (UK) BIM Technology Protocol For ARCHICAD v2.0 - Section 7.4
  3. BS 1192:2007+A2:2016 Collaborative production of architectural, engineering and construction information - Section A2 & A3.
  4. Building Information Management - A Standard Framework and Guide to BS 1192. Mervyn Richards - 2010 -  Section 6.2: Origin and orientation.
  5. BIMForum Level of Development Specification 2016 Draft for Public Comment - "Origins: Basis for all LOD". This section was subsequently removed from the final LOD Spec 2016. 
  6. BuildingSmart Australasia - Initiative - "Model Setup IDM" - Just released: July 2017.
  7. COBie 2.4 - Workbooks: "COBie.Floor.Elevation": Relative height to primary building entry Level.
    "COBie.Attribute" Facility Geo‐location:- Longitude, Latitude, Elevation & Rotation.
  8. New Zealand BIM Handbook - Appendix A - Modelling and documentation practice - Section 4.3 – July 2014

10.1.4:- Please advise if you are aware of any other industry standards in regard to Model Establishment.

 11. Surveying Accuracy:
11.1.1:- Land Surveyors are the best in the Construction Industry at measuring, however, they will be the first to admit that; “no measurement is ever completely accurate”. If you have ever had two different surveyors generate a Land and Feature Survey of the same site, you will be surprised how misaligned the CAD surveys “can” be.

11.1.2:- Incorrect Setup: However it seems many Building Discipline CAD operators have the expectation a building feature or property boundary line corner on a CAD survey is an absulute point and can be used as a local site origin point when transposing geometry from Real World Coordinates (Geodetic Coordinates) to a local site origin. The problem is, between surveyors CAD geometry, the chosen point can be out by up to 50mm. 


11.1.3:- Accuracy Standards: When you look at the Australian Victorian State “Surveying (Cadastral Surveys) Regulations 2015 - S.R. No. 43/2015” you can start to appreciate the level of tolerances surveyors work to:


"7            Accuracy of surveys
              (1)         A licensed surveyor must ensure that—
              (a)         the internal closure of any cadastral survey is such that the length of the misclosure vector does not exceed 15 millimetres + 100 parts per million of the perimeter; and
              (b)         the misclosure vector is determined as Ö (a2+b2) where "a" is the misclosure in eastings and "b" is the misclosure in northings; and
              (c)          all lengths are measured or determined to an accuracy of 10 millimetres + 60 parts per million.
              (2)         A licensed surveyor must ensure that all directional and angular measurements are verified.
              (3)         If a cadastral survey requires the determination of a boundary to be related to the Australian Height Datum, a licensed surveyor must ensure that the precision of the levelling survey is 12Ök millimetres where "k" is the length of the survey in kilometres measured in one direction along the levelling route.
              (4)         In making a cadastral survey to determine the location of boundaries to be defined on a plan by reference to buildings or parts of buildings for which no dimensions are to be shown, a limit of error of 50 millimetres in any one measurement or one part in 200 (whichever is greater) is allowable."
11.2:- Engaging a Local Site Origin:
11.2.1:- The bottom line is using any CAD geometry to represent a Building or Structure Feature or property boundary line is not repeatable. When you get a Survey in Real World Coordinates (i.e. Geodetic Coordinates), and there is a requirement to transpose the geometry to a “Local Site Origin” due to the 64 Bit floating point precision limitation, using an Easting and Northing Site Map Grid intersection is the best repeatable method.

11.2.2:- Site Map Grid: Engaging a Site Map Grid is also easily understood by the model recipient, even if it is the first time they have come across this method, and; in the event, a translocation error has occurred, it is easy to identify and resolve.


11.2.3:- Site Local Origin: It is also recommended the Site Map Grid origin engaged is to the nearest 100 meters, as what ever the Grid spacing the consultant uses, it will always be a multiple of 100m.

12. IFC File model origin:
12.1.1:- When Authors exchange digital model files between BIM/CAD applications, there is an assumption the Models exchanged have a single repeatable origin point. The thing is; various BIM/CAD authoring applications read and write the IFC model origin differently. Let me try to explain:

12.1.2:- Site Local Placement: When you dig down to how Spatial Elements are placed in the IFC schema, it uses a series of subsequent relative local coordinate systems call “Ifc Local Placements”. Here is a possible example:

   Site Local Placement (Can be relative to the Geodetic Origin or Real World Coordinates) ↵
        Building Local Placement (Relative to the Local Site Placement) ↵
              Building Story (Level) Local Placement (Relative to the Building Local Placement)
                   Space (room) Local Placement (Relative to the Story Local Placement) ↵

Note: There are exceptions to the above, and it can change from software to software.

12.1.3:- Survey Point: “Building” modeling authoring applications which facilitate a Survey Point (e.g. Revit & ArchiCAD 20+) will “tend” to:
  • Export the IFC model using the Survey Point (Can be the Geodetic Origin).
  • Import the IFC model using the Site Local Placement Origin, and negatively offset the Survey Point to the Geodetic Origin.

12.1.4:- Traditional BIM: “Building” modeling authoring applications which do not facilitate a Survey Point (e.g. Vectorworks & Tekla) will “tend” to:
  • ·Export the IFC model from the Internal Origin, with the Site Local Placement relative position set to 0,0,0.
  • Import the IFC model using the cumulative value of the relative Local Placement origins.

12.1.5:- Traditional Civil: “Site” Modelling Authoring Applications, typically working to Geodetic Coordinates relative to the Internal Origin (AutoCAD-Civil 3D & 12D); “tend” to:
  • Export the IFC model from the Internal Origin, with the Site Local Placement relative position set to 0,0,0.
  • Import the IFC model using the cumulative value of the relative Local Placement origins.

12.1.6:- Revit Elevation Error: In addition to the above, Autodesk Revit has its own way of reading and writing to the Site Z and Elevation setting, resulting in varying import and export results (refer to this LinkedIn thread in the IFC Group).

12.1.7:- Round Tripping: With the above different software approaches, it is very difficult to round trip IFC Models using default BIM Authoring Applications Import/Export settings. 

12.2: Software Vendors wangled a way to make IFC certification easy to achieve.

12.2.1:- The below quote is an excerpt from LinkedIn IFC Forum: Thread: “How are Revit coordinates exported to IFC?” Quote:  Bill East – May 2017, and it starts to explain why IFC round tripping is so difficult to achieve.

“There are multiple types of geometric representations in IFC. The IFC Coordination Model View Definition does not require optimal (or even a specific) representation for specific element types. Thud (Thus) design software programmers select(ed) the representation schema that causes them least effort. People who created the Coordinator view (Coordination View 2.0) did this to allow software to be easily certified because that's who went to the meetings.”

12.3: Achieving IFC Origin Consistency:
12.3.1:-  To mitigate the above IFC origin Import / Export variations; we recommend “Zeroing Out” the Survey Point (Local Site Placement Origin) identified in the above “12.1.3 Survey Point”.  This removes much of the uncertainty when exchanging models.

13. BIM Authoring Tools Translocation capabilities:
13.1.1:- From the above points 3, 4, 5, 11, 12, it is understood we need to facilitate both Geodetic and Local Site Coordinate Sytems in a project. However, many BIM Authoring applications are very weak at transforming models/geometry, on Import or Export and in many situations when tasked with a transform of UTM Coordinates (up to 10,000km) fall short.

13.1.2:- Not 100% Repeatable: This is even the case with Authoring Applications under the same Software Vendor umbrella. An example of the is linking Autodesk AutoCAD .dwg files into Autodesk Revit using the Shared Coordinates (Survey Point) to carry out the translation. This approach is not 100% repeatable and can fall over depending on how the DWG element content is generated.

13.1.3:-  Middleware: To increase the reliability of the Translocation, executing it within received native file format, or using a middleware application will enable a more reliable workflow. Some Middle-ware software examples enabling translocation tools sets include; Datacubist SimpleBIM for IFC files, Autodesk AutoCAD for DWG & DXF files.

B:- Close
B.1.1:- I can confirm, it is possible to establish a site set-up process to include almost all the above consideration. Any Design Lead firm sharing BIM models, need to take the initiative to develop and document (flowchart) the final process. 

B.1.2:- This workflow is then circulated to all relevant parties.
If you are a design consultant, insist you are provided with such a document by the Design Lead. Ensure you thoroughly test it and check it does not adversely affect your workflows. The consultants are the party most likely to be directly impacted in the event a building relocation is inadequately planned.

 B.1.3:- There is no one item mentioned here which is difficult. An all-encompassing plan does take a while to develop and test. Yet it is one sure workflow all lead consultants need to have.

C:- Call for Review
C.1.1:- For any readers, reviewing the above and taking issue with any of the premises, I request you please provide Brian Renehan (the author) with the relevant constructive feedback (via below comment or email - see contact info). Identify the background and reason for your counter-argument. The above premises “should” be universal for all building construction projects. If it led to universal software specific workflow outcomes, it would greatly benefit the industry.
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