Thursday, August 9, 2012

Revit point cloud works

I recently worked on my first point cloud project. This was a industrial project modelled to help plan a reorganization of a part of a building. The technology is not as easy to use as it seems to be.

Here are some things you will have to keep in mind if you attempt to model a building steel structure from a point cloud :

  1. First select the scanner to be used : there is many types of scanners. Some of them scan in color (it take pictures while scanning and project the images on the points to color them) and older ones can only scan in black. Color may be helpfull to help you understand wich kind of object is reprensented by the 3D points.
  2. Sometimes the cloud is not enought dense and compact to understand the geometry. Unlike architectural modelling, building structure need much more accuracy to be able to determine wich steel section is to be modelled. This have been said, to get all the information required to match you "place holder" column to the real one you need all the dimensions (D, B, T) of the column to match it with the corresponding shape in the handbook. I suggest you scan more "stations" to get 3D points from more view angles. Remember that : what you see is what you get !
  3. Usually deflection (Yielding zone) of beams & columns and the utlimate physical limit (Plastic Zone) are 2 phenomena very difficult to observe on existing buildings. However this is something you can see by measuring the point cloud or simply by looking at it when the deformation is very high, wich I hope you will not see on your project. Make sure you define the LOD (Level Of Detail) required for the purpose of the current project. If you model is intended to be used for reinforcing the building structure you may want to see wich column is still at it maximum capacity or if this columns is to be replaced due to distortion. If you only need to get clearance from the model, you may not need this LOD so modeling it straight as it was shown on conceptual stage of the project should be enought. 

Luckett & Farley structural engineers used 3D laser scan to construct a Building Information Model (BIM) for a project. A series of scans in and around a chamber structure helped generate millions and millions of data points. The collective of points created a Point Cloud file, which Revit 2013 recognized and could be sliced, diced, and manipulated to see what was happening in the chamber.

Read more here!

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