Modeling through Laser Scanning for BIM

What is Scan-to-BIM?

The process of generating BIM models varies in new buildings and existing buildings. For new buildings the process includes updating as-design BIM model based on the most recent alterations during the construction phase to generate the as-built BIM model. Distinctively, since most of the existing buildings are devoid of any previous BIM records, a BIM model is generated out of an existing building by capturing geometries of building elements to form the object through a 3D laser scanner. The objects formed by capturing geometries should be equipped with semantic property and attribute information to create a BIM family object.

Scan to BIM is the course of formulating accurate digital representation of a physical space by importing and calibrating raw scanned data that can be expended for designing, assessing progress and evaluating options.

It is an accurate, reliable technique which automates the process to decrease the required time and cost for creating BIM model and improve the documentation and visualization.

Laser Scanning and Point Cloud Data

The primary stage in the scan to BIM process is capturing existing building conditions. A high-quality captured data is a prerequisite for the precision of the model, determining LOD and the required time and efforts to create the model.

While capturing data there are several techniques that can be taken into consideration categorized into contact techniques and non-contact techniques. Image-based, range-based and other techniques clusters are classified under the Non-contact techniques whereas Contact techniques include manual techniques.

Of late, a few of the high-tech options growing in popularity are LiDAR scanning & Photogrammetry to help in the collection of data. Both methods produce point clouds with vectorized data which means everything can be measured.

To enable digital representation capture of a space, 3D imaging systems, such as laser scanners are used, that rotate at a higher speed allowing the laser beam to hit various objects and materials. Resultantly, a piece of digital data is recorded due to the relative position of the beam to the scanner and other elements of the site or buildings. This is termed as points. A large collection of these points begins to build a highly accurate Three-dimensional (3D) digital picture of a space or site being scanned known as point clouds.

The second stage in the scan to BIM process or the registration stage is the post processing phase, where multiple scanning stations is stitched together.

The final stage of the scan to BIM process is converting this raw point cloud data automatically to structural elements and terrain features to generate accurate geometric data of potential building rudiments such as porches, pipes, beams, columns, ceilings, mechanical, electrical and plumbing fittings, topographies and urban landscapes, create sections, set work points, measure distance to and from points in the cloud and visually compare the Revit model against the point cloud.

Benefits of Laser Scanning

  • 6D Facilities Model– The foremost benefit of scan to BIM is embraced for operating facility throughout its life-cycle. As-built condition model allows for a proactive building management by investigating and understanding the installed position of elements from the model and plan a tactful approach.
  • Clash Detection– Another key benefit of scan to BIM is to create as-built BIM models for MEP services that help the managers provide early clash detection.
  • Human Errors– Laser scanning removes a great degree of human errors from surveying process.
  • Improved Collaboration– Scan to BIM enables improved transparency, communication, and collaboration.
  • Collection of Data- Laser Scanning enables significantly high volumes of data to be collected over a considerably shorter period.
  • Reliable and Efficient- BIM models generated from the scan data allows more reliability & quality assurance.
  • Faster Decision Making- Scan to BIM simplifies project alterations and assists in faster decision making.
  • Better Sustainability- Use of BIM throughout the building process ensures better sustainability in the project.
  • Cost Estimation- Minimize construction cost estimation errors with the virtual creation of BIM model from scan data.

Best Practices of Scan-to-BIM

  • Before you start the modeling, establish the LOD and know the final use of the model.
  • Use conversion tools to convert Point Cloud data automatically to Revit models.
  • Develop consistency by making consistent assumptions.
  • Communicate and understand the requirements ahead of time.
  • Always lock down after the point cloud file has been inserted for consistent accuracy.
  • Have different work sets for each point cloud file.
  • Use multiple views and avoid generic models.

Conclusion

The implementation of scan to BIM brings an entirely new realm of possibilities for existing building conditions. Accurate and efficient 3D modeling capabilities by scanned data have made scan to BIM a competitive advantage for contractors willing to invest the time and effort into this fully integrated BIM workflow.

Contact us if you need any assistance in converting AutoCAD and Point Cloud data to efficient and accurate three dimensional models that can be further used of clash detection and facility management purposes.

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