September 12, 2011

Lidar and Points Clouds – Are You Up in the Air?

During support at Ideate, there are a lot of questions and a little bit of confusion over this topic, so I decided to blog about it. More and more customers have been requesting information on how they can work with Point Cloud or Lidar data within their Autodesk products. Depending on which application you’re using, the Point Cloud and Lidar functionality may be completely different. And, Point Clouds and Lidar Data are two different things.

  1. Lidar data is collected by Laser Scanners (sometimes referred to as Laser Scan data).
  2. There are many different types of scanners and scanning methods available. The most common these days are Aerial, Ground Mounted and Vehicular Mounted scanners.
  3. Lidar data files are generally raw data (lots and lots of numbers) that need to be processed or indexed before they will appear in a drawing file
  4. Lidar Data files are usually very large and contain thousands, or millions, or billions of points.
  5. There are many different file formats for Lidar Data. Not all formats work with all programs.
  6. Lidar data files sometimes include more data than necessary. Different applications can be used to filter the data before importing it into your file.  Trimble RealWorks has the ability to process raw data from Trimble scanners and output a Point Cloud file format for direct import.
  7. Scanners on today’s market now include color sensitive lasers. Color information can be included with a scan to assign a color to each point, creating a more realistic appearance for the point cloud.
  1. Point Clouds are created from Lidar and other point data sources, and are usually in database format for Autodesk applications.
  2. The common Point Cloud files used in Autodesk products are .PCG and .ISD (ISD files also have associated PRMD and IATI files) but there are others out there.
  3. The latest releases of AutoCAD Civil 3D will process raw Lidar data, allowing users to create a point cloud database (ISD format). AutoCAD based products, Revit products and Navisworks can also process some forms of raw data.
  4. Civil 3D works on a different processing engine from the rest of the applications, so the results will vary depending on what application is used, even if the same source file is used.
  5. Civil 3D Surfaces can be created from Point Cloud data
  6. Point Clouds may appear in color IF the scanned data included color readings.
Here’s an overview of what you can expect from the different 2012 Autodesk Applications. You may be surprised by how many of the current Autodesk products include Point Cloud and Lidar functionality.
The screenshots below are some samples of what you may see when opening or processing point cloud and laser scanned data in some of the Autodesk applications. The source file is 760MB, in PTS format and includes roughly 18 Million points. This file took just under 20 minutes to process on a 64-bit Windows 7 machine with 8 GB of RAM.

In these examples the PTS file was used to create a Point Cloud (ISD) database in Civil 3D. The resulting ISD database was then opened in the respective applications. In Navisworks, the Civil 3D drawing (DWG) was opened directly rather than the ISD database.

Because Revit products do not support ISD format files, a PCG created from a laser scan of a parking lot was used.

Civil 3D 2012 used to “create” a Point Cloud (ISD)
from PTS file
ISD File (created by Civil 3D) Opened in AutoCAD 2012
Civil 3D DWG file (with saved Point Cloud)
opened in Navisworks Manage 2012

PCG (ISD Files are not supported in Revit) file
inserted into Revit Architecture

As you can see, the results of importing and processing Point Cloud or Lidar data will vary depending on what application is used. For best results, identify the type of data you are working with ahead of time to make sure it’s compatible with your application of choice.

Happy Scanning! 

Matt Miyamoto, P.E.
Infrastructure Solutions Application Specialist

Matt is a licensed Civil Engineer in the state of Hawaii. Matt obtained a BS in Mechanical Engineering from the University of Hawaii at Manoa, and has 7 years of private sector design experience which he applies in his role as an application specialist with Ideate, Inc. His project experience includes residential and commercial site development, private and public sewer, water and drainage systems, harbors improvements, and roadway improvements. While in Hawaii, Matt was involved in multidisciplinary projects for City and County agencies, State Departments, the Army COE and private developers. @MattM_PE

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