If you want to enable 3D view for PDF documents, there are several ways to do it. One of the most popular methods is to use Adobe Acrobat, which has built-in support for 3D content. Here's how to do it:

1. Open the PDF document in Adobe Acrobat.

2. Look for the 3D content within the document. It may be embedded within a specific page or as a separate attachment.

3. If the 3D content is embedded within a page, you can activate the 3D view by clicking on the 3D model and selecting the 'Activate 3D' option from the context menu.

4. If the 3D content is a separate attachment, you can open it by clicking on the attachment icon and then selecting the 'Activate 3D' option.

5. Once the 3D view is activated, you can interact with the 3D content using the various navigation tools available in Adobe Acrobat.

If you don't have access to Adobe Acrobat, there are other software options that can enable 3D view for PDF documents. For example, some third-party PDF viewers and editors also support 3D content, so you may want to explore those options as well.

Enabling 3D view for PDF documents can enhance the viewing experience and allow you to interact with 3D models and visualizations in a more immersive way. Whether you're working with engineering drawings, architectural designs, or educational materials, being able to view 3D content within PDF documents can be a valuable feature to have at your disposal.