When I open some of our 3D PDFs the model tree opens as soon as the user activates the canvas. We would like to prevent this happening.
Or is this a property of the file that needs to be changed when it is created in Acrobat?
Not with a script - you set this as a preference on the 3D annotation. Right-click it and choose Properties, then on the 3D tab untick the "Open model tree" item and save your file.
Retrieving data ...