The National Center for Biotechnology Information (NCBI) has created iCn3D 1.0 ("I see in 3D"), a new WebGL-based viewer for interactive viewing of 3D macromolecular structures and chemicals on the web. Users no longer need to install a separate application to view structures. With iCn3D 1.0, users can:
The source code for iCn3D is available from GitHub for developers who would like to customize the program and/or contribute code, and for users who would like to run the program on their local computer.
For those who still would like to use Cn3D, the executable program version of the 3D structure viewer, it is still available; you can still access structures in the "Download Structure Data" portlet by selecting "Download: ASN.1(Cn3D)".