SCAN TO BIM PROCEDURE (Surface Reconstruction)

Point Cloud scan comprises of a set of a million data points which represent the three-dimensional coordinates of the external surface of a building or an object. This set of data called the point cloud are typically gathered or captured using a 3D laser scanner. Using a variety of surface reconstruction methods facilitated by specialist point cloud processing software tools, we reconstruct this scan data into a working 3D BIM model which reflects the existing condition of the building or structure.

 

Making use of our extensive experience in wide range of point cloud conversion projects from architectural, structural and MEP streams, we have developed a unique and streamlined workflow for BIM modeling from point cloud scan combining the standard procedures followed in the AEC industry with innovative technology to give you an accurate and reliable solution.

The process of converting the captured 3d point data into a usable intelligent model is cumbersome, time consuming and expensive. It requires intensive expertise in handling the point cloud as well as rich experience in BIM modeling. The process of converting the point cloud to polygon or triangle mesh models, NURBS surface models, or CAD models through a process commonly referred to as surface reconstruction.

Point Cloud Modeling Procedure

Point Cloud Data Review

 
Scanned Point cloud data from 3D scanner is reviewed using ReCap or CloudWorx™ add-on software which helps in reviewing & visualizing the building in context with the existing environment. Real photographs of the as-built site are an added advantage and enables better visualization of the services present. 

Modeling

 
The architectural/structural/MEP elements are modeled from the point cloud data by working in section and/or plan view. The point cloud data is imported to the modeling software to be used. Most of the 3D software from Autodesk such as Revit Suite, AutoCAD, Civil 3D, Inventor and 3ds Max can be used for point cloud modeling. SOLIDWORKS® 3D CAD and SketchUp can also directly work with point cloud files. Once attached to a drawing, the point cloud can be modified and used as a guideline for drawing. An unlocked point cloud is modified in several ways depending on the size such as like, filtering, modifying, editing and colorstylizing. The file size being huge, it helps to crop the focus area thereby minimizing the memory usage. The number of displayed points is controlled for an optimum program performance and reduction in visual noise. The density of displayed point clouds is changed during Pan, Zoom, or 3D Orbit. Lowering the real-time density degrades the point cloud display during panning, zooming and orbiting, but makes those operations quicker.

Model Review

 
Modeled elements and services are reviewed using Navisworks by simultaneously appending both model and point cloud files. At the time of modeling it is difficult to depend only on point cloud data. So, it is reviewed using Recap and Naviswoks as modeling progresses. Review and comparison is done using the site photographs and Photosphere.

 

Inputs expected from Client side:

  • Laser color/monochrome scanned data of the building to be converted
  • Real photographs and Photosphere of the building
  • Final model and design drawings if available

Technology/Software’s used

  • AutoCAD
  • Civil 3D
  • Inventor
  • Navisworks Manage
  • Revit Suite
  • 3ds Max
  • SOLIDWORKS® 3D CAD
  • Trimble SketchUp