It's not possible within the native Acrobat toolset.
In Acrobat 8/3D, a copy of "3D Toolkit" was included in the bundle (an OEM version of Deep Exploration) that could make pretty much any edit you wanted on a 3D file.
In Acrobat 9 Pro Extended, a new Adobe application (3D Reviewer) was bundled that could make some very basic changes, but nothing detailed.
In Acrobat X, no editing of 3D models is possible and no bundled software is provided to import or edit 3D files prior to their placement in a PDF file. To work with the models before import, assuming your existing software can't write the data in the format you want, you will need to purchase additional software (Deep Exploration, the Tetra4D toolkit, etc.).
In Acrobat 8/3D, a copy of "3D Toolkit" was included in the bundle (an OEM version of Deep Exploration) that could make pretty much any edit you wanted on a 3D file.
In Acrobat 9 Pro Extended, a new Adobe application (3D Reviewer) was bundled that could make some very basic changes, but nothing detailed.
In Acrobat X, no editing of 3D models is possible and no bundled software is provided to import or edit 3D files prior to their placement in a PDF file. To work with the models before import, assuming your existing software can't write the data in the format you want, you will need to purchase additional software (Deep Exploration, the Tetra4D toolkit, etc.).