Tag Archives: Technical Requirements

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.