Acrobat User Community Forums

Rather than use a separate button, you could try using the 2D image as the poster for the 3D Annotation. Then when the 3D Annotation is not active, you will see your 2D Image. Users would then click on the 2D image to activate the 3D Annot.

You can attach any file type that can be converted to PDF to be the poster of a 3D Annotation when you embed the 3D object on the Conversion properties dialogue on
Poster section of the 'General Tab'. You can also do this anytime afterwards by using the "Select Object" on the Adv. Edit toolbar to select the 3D Annot, then right click and choose 'Properties' and then 'Edit Content' and choose the appropriate Poster setting that allows you to attach a file to be used as the poster.