Guidelines for Using Building Information Modelling – Essential Views

5.1.1 Essential Views

The BIM file should contain the following views, if applicable, but not limited

to:
(a)	Block/ Key plan
(b)	Floor plans
(c)	Sections
(d)	Elevations
(e)	Typical details
(f)	Emergency vehicular access (EVA) diagrams
(g)	Open space diagrams
(h)	Fire compartment diagrams
(i)	Site area and site coverage (SC) diagrams
(j)	GFA diagrams
(k)	Usable floor area (UFA) diagrams
(l)	Usable floor space (UFS) diagrams

Assessment of prescribed windows
Diagrams showing compliance with the Sustainable Building Design (SBD) Guidelines

Guidelines for Using Building Information Modelling – Essential Views for Composing the Prescribed Plans

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Essential Views for Composing the Prescribed Plans

APs are recommended to set up the following views with sufficient information to demonstrate compliance with the BO and its regulations, relevant codes of practices, PNAPs and circular letters issued by the BA. For the verification of areas and dimensions as proposed in the prescribed plans using the submitted BIM file, the following views shall be included in the file composition.

Guidelines for Using Building Information Modelling – Technical Requirements 3D Model

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5.1.1 3D Model

The BIM files should contain a 3D computer model representing the proposal on the site with its immediate surroundings. The model includes data of building components externally and internally, such as internal partition walls, internal staircases, building façades, windows, projections, architectural features, etc.

The 3D model should be able to be rotated in all directions for checking, viewing, zooming in/out, etc. by utilizing the functions of BIM software to facilitate inspection of building components and virtual walk-through of the building model in the first-person view.

Guidelines for Using Building Information Modelling – Technical Requirements Colour Code System

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5.1.1 Colour Code System

This paragraph aims to introduce two colour code systems.

(a) Building material and description on floor plans

PNAP ADM-9 specifies that every plan submitted for approval should be coloured to differentiate existing works from proposed new works. The preferred colour code as shown in Appendix A of PNAP ADM-9 should be adopted.

(b) Gross Floor Area (GFA) diagrams

The preferred GFA colour code as described in Section 5.2.10 of the Guidelines should be adopted.

Guidelines for Using Building Information Modelling – Technical Requirements Spatial Location and Co-ordination

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5.1.1 Spatial Location and Co-ordination

The BIM origin point and orientation of the model should be based on the actual location of the development by referring two widely used Hong Kong geodetic horizontal and vertical control networks, namely the Hong Kong 1980 Grid System (HK 1980 Grid) and Hong Kong Principal Datum (HKPD).

The HK 1980 Grid and HKPD should be presented in metres corrected to three decimal places (i.e. (8XX,XXX.XXX mN, 8XX,XXX.XXX mE) and (X.XXX mPD). Negative sign should be added for negative mPD (i.e. – X.XXX mPD).

Guidelines for Using Building Information Modelling – Technical Requirements Mathematical Modelling

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5.1.1 Mathematical Modelling

All dimensions should be true dimensions generated automatically by the software. Numerical dimensions inputted manually in the BIM file are not acceptable.

Guidelines for Using Building Information Modelling – Technical Requirements Unit and Measurement

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Unit and Measurement

The model should use consistent unit and measurement across the project with default drawing units in millimetres (mm) with a precision rounded up to the nearest mm unit.

All floor areas and volumes should be presented in square metres (m²) and cubic metres (m³) respectively and rounded off to three decimal places.

All site areas should be rounded off to the nearest 0.1m² for site area less than 2,000m² and to the nearest 1m² for site area of 2,000m² or above in accordance with PNAP ADM-21.

Guidelines for Using Building Information Modelling – Specification for Native File

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1. Specification for Native File

The native file should contain the building proposal model and complete with all views, schedules, calculations and annotations essential for the production of the prescribed plans. All BIM submissions should adopt a unified modelling methodology, and the native file should be created in a standardised file structure.

Guidelines for Using Building Information Modelling – Level of Development

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4.1 Level of Development

BIM technology enables the BIM model to contain geometrical and non- geometrical information as BIM elements. Geometrical information includes size, volume, location, orientation, etc. while non-geometrical information includes specifications, performance data, cost, etc.

BD notices various international organisations attempting to standardise BIM elements. One of the popular standards is the “Level of Development” (LOD), according to the American Institute of Architect. The LOD is classified into six categories namely LOD 100, LOD 200, LOD 300, LOD 350, LOD 400 and LOD

500. Reference on the LOD classification and specification may refer to https://bimforum.org/ . As a general principle, APs are advised to adopt LOD 300 in the preparation of BIM files though on some occasions APs may adopt LOD below 300 (e.g. indication of E/M plants, exhausted ducts) or LOD above 300 (e.g. special design details).

Guidelines for Using Building Information Modelling – Administrative Requirements

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4.1 Administrative Requirements

The BIM files should be stored in a non-rewritable DVD-ROM in ISO/IEC 13346:1995 format (i.e. DVD format). Except otherwise agreed by the BA, all other electronic submission media are not acceptable.
- Each BIM file should be limited to the size of 500MB. Each BIM file should contain 3D model, views, schedules, as well as the pre-set drawing sheets including plans, area diagrams, calculations, etc. for the production of the hardcopy of prescribed plans. The text file should be included in the DVD-ROM to describe the linked files’ hierarchy structure.
- BA currently accepts BIM native files created by (i) Revit version 2017 or later and (ii) ArchiCAD version 21 or later only. As BIM technology is fast developing, there may be add-ons assistant programs or in-house scripts used for enhancing automation in the BIM file production. Add-ons or other implanted automation may cause the submitted BIM file not usable by BD’s standard Revit or ArchiCAD software. It is the APs’ responsibility to ensure that the purposes of the BIM model are served, as elaborated in the Guidelines, without relying on add-ons or additional scripts.
- The use of software, other than Revit and ArchiCAD, requires prior acceptance from the BA. As a general rule for such prior acceptance, the APs should submit at least one test sample together with the enabling software to the BA for installation and testing. For the avoidance of doubt, BA does not accept any web based BIM software.
- Revit files should be saved in “.rvt” format and ArchiCAD files in “.pla” format only. All other lightweight, compressed or zipped file formats such as “.dwf”, “.dwfx” and “.bimx” will not be accepted.
- Drawing title blocks with drawing number, revision number, legends, site

/ project title, drawing title, etc. as detailed in Section 5.4.1 should be inserted in every drawing for identification purpose.

BIM files submitted in DVD ROM format should be self-contained and detached from the originating server. It shall be able to be opened on any standalone computer with the abovementioned software. All “X-Ref” files for the BIM model such as xlsx and pdf files should be stored in respective sub-folders in DVD ROM, and the link between all “X-Ref” files and BIM main file should be appropriately connected.