Working with large models and the Google Earth Extension for AutoCAD

The Google Earth Extension for AutoCAD allows you to view your drawings in Google Earth. The user guide provides easy to follow steps for importing a Google Earth image into AutoCAD, publishing 3D model to Google Earth, draping a Google Earth image onto a 3D mesh in AutoCAD, and attaching time span (time is often referred to as the 4th dimension) information to your model.

Software Architect, Thomas Inzinga, is one of the team members who responds to feedback that comes in via [email protected]. In working with AutoCAD users he recently noted:

1. There is a limit to the number of faces that can be published to Google Earth when publishing with the "Materials" toggle turned on (approximately 22,000 triangles).

2. If you get an "out of memory" error, it means that your model is too big for Google Earth to handle. When this happens, you can publish your model using the AutoCAD Google Earth Extension in several pieces:

   • On the "Items" page of the publishing Wizard, there is an option to either publish all entities in an AutoCAD model space, or selected entities.
   • One would need to break the model into logical pieces and then publish each piece, one-by-one. Logical breakdowns might be by layer, by geographic area, by drawing (for a case where many XREFs are present), or by some other partitioning scheme.

   KML files up to 100 MB in size work well in Google Earth.

3. If the GeoReference information is not set up properly, the coordinates in the file put the data near downtown San Francisco. This is the default position if the data on the GeoReference page is not modified. The user guide contains information on GeoReferencing a model.

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