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Refurbishment and renovation projects in the AEC industry typically involve old buildings where modifications in the architecture, structure and MEP systems in the building are typically not recorded or updated for years. When undertaking a refurbishment project, the extent of the renovation depends on whether it is the building being completely stripped or it is the plan to use some of the existing the MEP elements. One of your main requirements in a refurbishment project is to start with an accurate as-built model which provides detailing of the architectural, structural and MEP elements of the building.

One of the methods which you could use, to capture the as-built conditions of a building, is to re-create the model using point cloud modeling. Point cloud modeling involves 3D scanning with high-end laser scanners which measure and map millions of points of building objects and surfaces. Compared to a manual survey, point cloud data models are much more accurate and provide more certainty.

For the laser survey itself, once the laser scanning instrument is placed, a laser scanner rotates on a tripod and uses light rays to gather the 3D location of surfaces and objects. Within a matter of few minutes, the scanner collects millions of data points (also known as a ‘point cloud’) to create a 3D as-built representation of the building space. This data is then exported into a point cloud data file, typically a CAD or BIM software platform add-on, ready to develop an intelligent 3D model.

During the process of laser scanning, 360-degree photometric images are also obtained to identify objects which are not distinguishable in the point cloud data. The scanned point cloud data and the photometric images are sent to 3D modellers who build 3D architectural and if needed, the MEP elements of the building. To facilitate the successful conversion of point cloud data to a 3D model, you need to consider the following requirements:

1.    Point cloud data:

Laser scan – A 3D laser scan needs to be conducted of the building that requires refurbishment. With the lack of reliability of as-built drawings, laser scans provide depth required by modellers to create a 3D model. For MEP elements, laser scans must be accurate to ensure retrofitting of additional MEP systems that ensure a clash free model.

3D photography –
Together with laser scans, 360-degree photometric images must be photographed to provide architectural modellers and MEP (M&E) design consultants with an understanding of the objects in the building environment.

2.    Level of detail (LOD):

Depending on the requirement of the refurbishment project, the LOD must be specified to allow scanning professionals to understand the extent to which a scan must be conducted. If MEP elements should be retrofitted, a precise laser scan with detailed point cloud data is required.

3.    Tolerance levels:

In 3D architectural modelling, when MEP elements from a point cloud model are extracted, there is an extent to which corrections can be made. Tolerance limits and camera angles must be decided by the architect or scanning professional at the outset of the project before a laser scan is conducted. Tolerance levels provide modellers with leeway when designing 3D architectural and MEP models from point cloud data.

3D architectural modelling and MEP modelling from point cloud scans requires accuracy and experience of understanding spatial relationships of structural elements in a building.

With new software programs, the data from models can be exported to several mainstream CAD platforms after clash detection is performed. There are ‘smart point cloud’ and ‘point cloud to BIM’ software programs which can convert a laser scan of point cloud data into 3D BIM models. By utilising new software programs one can develop accurate, installation-ready and clash-free models.

At XS CAD, our scan to BIM service provides accurate models for as-built purposes and for retrofit, refurbishment and renovation projects. We use raw survey data and images from tools such as Leica Geosystems or from other laser survey tools and a range of specialist software tools, including Cloudworx to create accurate architectural and MEP models that reflect the current state of the building. We combine scan to BIM models for existing buildings with models for new/renovated areas of a building. Our LEED accredited team of BIM modelers, BIM coordinators and MEP designers in India, have extensive design experience and utilise BIM as an effective design tool. To find out how you can convert point cloud and laser survey data into sophisticated 3D BIM models, contact us.

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