NCBI's web servers send data to Cn3D using the MIME type chemical/ncbi-asn1-binary. So in order to launch Cn3D properly, you need to configure your browser so that it knows where Cn3D is and that it
should use Cn3D when it receives a file of type chemical/ncbi-asn1-binary. General instructions on setting this up in the common web browsers follow below.
To test whether your configuration is working, click on the image below, which should launch Cn3D 4.3 and should show a structure and viewpoint very like what's shown in this image:
Click here to test Cn3D!
Some browsers will let you choose an application when opening up a new
MIME type. Try clicking on the image above, and if your browser gives you
an option to "open with," point it to the Cn3D application in the folder
where you installed Cn3D 4.3. Then quit Cn3D, and click on the above image
again to see if it now works automatically.
If not, look below for hints on how to set up specific browsers. You
may need to consult your system administrator for help.
Go to the Edit:Preferences panel, and open the
Navigator:Applications area (some versions call it Helper
Applications). Create a new type (or Edit, if it already exists), with
the MIME type chemical/ncbi-asn1-binary, and in the Application
box, put in the path to Cn3D. Some older versions require a "%s"
after the executable path, or you may get
Cn3D opening but with no structure. For extension you can use ".cn3", and for description something
like "NCBI Chemical Data".
Configuring Internet Explorer
On Windows, this should be done by the installer. If not, you'll need
to set up a new file type in Explorer that associates the extension ".cn3"
with the MIME type chemical/ncbi-asn1-binary and the Cn3D.exe
Go to the File:Preferences panel, and select the Applications
area. In the File Types, create/edit a type that uses
chemical/ncbi-asn1-binary as the MIME type, the extension ".cn3", and
in the Application field put in the full path to Cn3D.
Note to Macintosh Users:
Configuring helper applications on browsers under OSX seems to be
difficult or impossible. This is a limitation of the browsers, not of Cn3D
itself. On our test platforms, we have only been able to get Netscape to
work properly with NCBI structure-related web pages. In particular, Safari
has no mechanism at all for configuring helper applications. However, you
should still be able to save data files to the desktop or a download
folder, and then drag & drop files onto Cn3D to launch it manually.