Unfortunately RadPdfViewer does not support 3D PDF documents. Moreover, the PDF viewer is 100% WPF based code and it uses no other 3rd party solutions to display embedded content and we have no plans about changing this in the future. In this case as the documents you need to render are quite complex, we could suggest you to embed Adobe Reader Active X control in your WPF application in order to achieve 100% compatibility. Please take a look at the following blog we found on the matter:
Let us know if this helped.
the Telerik team