System Requirements:

• OSX 10.1 or higher.

Download Cn3D 4.1 here:

ftp://ftp.ncbi.nih.gov/cn3d/Cn3D-4.1.OSX.zip

Simply download the archive via this link, and extract it into a folder on your system, wherever you normally put application software, using your favorite zip archive application.

Once done, see the instructions for configuring your browser.

Mac OS 8/9 Users:

Cn3D 4.1 will only run under OSX. For now, though, version 4.0 is still available, which has nearly all the features of 4.1 and runs on OS 8.6 or higher.

Download Cn3D 4.0 here:

ftp://ftp.ncbi.nih.gov/cn3d/old/4.0/Cn3D-4.0.0.sit

If you haven't already done so, you'll need to follow this link to download Apple's OpenGL extension libraries before you can run Cn3D 4.0, as it requires OpenGL.

Memory Requirements

If you have trouble running Cn3D 4.0 on Mac OS 8/9, especially on big or multiple structures, you may need to increase the amount of memory available for Cn3D:

• select the Cn3D application and
• go to "Get Info" in the Finder's File menu.
• increase the preferred and minimum sizes by at least a factor of 2 (or more if your Mac has more memory).