Issue with Point Cloud shifting or scaling when inserting into AutoCAD

05.02.2017

The issue is that the point cloud, once inserted into AutoCAD, can shift or scale

It’s almost common practice these days to export a point cloud from one piece of software to another. While this has become a common concept, you can still run into some issues. One such issue is when a point cloud is exported from Trimble Realworks to Autodesk ReCap and then to either Autodesk AutoCAD or Autodesk AutoCAD Civil 3D. The issue is that the point cloud, once inserted into AutoCAD, can shift or scale. The true issue lies somewhere between the exporting scale (International meters) in Realworks and the importing scale (US feet/inches). Even with a recent software update from Trimble (Realworks 10.3) that was released to fix the issue, the problem remains. So, you ask…what do I do to fix the problem? The answer is much simpler than you think. It doesn’t lie within the export or somewhere in-between. It lies directly within AutoCAD or Civil 3D. Everyone using AutoCAD is familiar with how units work, but many do not know that there is such a thing as “insertion units”. By default, the AutoCAD/Civil 3D insertion units are set to “feet”. This causes point clouds and even point files from a data collector to shift or scale in size. However, if the insertion units are changed to “inches” before inserting a point cloud, then the problem is solved. A simple fix for a major problem. As with any variable in AutoCAD/Civil 3D there are a couple ways to change the insertion units. Below is how to change the insertion units both ways:

From the command line:

  • Type "INSUNITS" and then use one of the following variables to change the scale. In this case you will use "1" for inches
    • 0 Unspecified (No units)
    • 1 Inches
    • 2 Feet
    • 3 Miles
    • 4 Millimeters
    • 5 Centimeters
    • 6 Meters
    • 7 Kilometers

From the Drawing Units Dialog box:

  • At the command line type “Units” and hit enter
  • In the middle of the dialog box you will see “Insertion Scale”
  • Click the drop down and select “Inches”
  • Click ok

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