Exporting to Google Earth KML

Google Earth KML files can be exported from JetStream. The exporter creates a compressed KML file with the extension .KMZ and supports the export of:

• Triangles

• Lines

• Materials (colour and flat transparency only)

• Viewpoints (adjustments may occur due to Google Earth limitations)

• Model Hierarchy

• Hyperlinks (currently only URLs work correctly in Google Earth)

1. From the File menu, choose Export, Google Earth KML... . This brings up the following dialog.

   

2. Select Export model relative to terrain height to put Google Earth in a mode where all heights are measured from the surface of the ground. When this is off all heights are measured from sea-level.

   Note

   When positioning a model relative to sea level, the height of the Google Earth reference points must also be measured relative to sea level. When positioning a model relative to the ground, the Google Earth reference points must be measured relative to the ground.

   Google Earth always places new placemarks at an altitude of zero, irrespective of whether that is relative or absolute.

3. Collapse on export allows different levels of collapsing parts of the model hierarchy in the exported file.

   • None ensures the whole heirarchy is exported

   • All objects collapses everything into one node

   • Files collapses each file into one node

   • Layers collapses each layer into one node

4. Limit number of Polygons should be enabled to restrict the amount of geometry exported into the output file. Geometry is selected on the basis of taking the most obvious objects in preference to the fine detail. If the exported file is too large for Google Earth to display, try enabling this and reducing the number of polygons. View, Scene Statistics in JetStream shows the number of triangles and/or lines in the current project. By setting a polygon limit you are choosing to export only some of these items.

   Note

   Google Earth's ability to handle large numbers of polygons is far more limited than JetStream. Hence it is worth noting that currently Google Earth will consider 1,000,000 polygons as being a big model.

5. The Origin position values are the first pair of reference points on the Google Earth surface, and must always be defined. The JetStream reference point will always be positioned to exactly overlay the Google Earth reference point.

   Second and Third reference points can be used, and if enabled then the position and orientation of the model can be more accurately defined.

6. Use the Import buttons to read-in saved placemark locations from KML files exported from Google Earth.

   The Origin Import button differs slightly from the other two; if the KML file contains multiple placemarks, this button will offer the user the choice of importing second and third reference points if available. The other two buttons will only import a single reference point.

7. The Pick buttons allow the reference point locations to be selected in the main 3D view.

   These points must be visible in the main 3D view prior to exporting, as once the KML Options dialog is open you will not be able to navigate before picking.

   Note

   You may wish to use View, Split to split the main 3D view enabling you to have separate views of each reference point.