The extension CDL is used by the 2D & 3D software CADKey. CADKey was a very popular and commonly used CAD program. In 2003, CADkey was bought by Kubotek, which renamed the software KeyCreator. KeyCreator can handle CADkey files and, according to Kubotek, is the only software that can reliably load, edit and convert all CADKey files.
The last versions (v20 & v21) of CADKey have also saved a new format with the extension ckd. Especially when importing into other 3D programs, problems can occur. The offered demo version of KeyCreator can also be used as a converter. Kubotek Sprectrum Lite also offers a free CADKey viewer.
Most often resolving problems with opening CDL files is very simple. Just install an appropriate program that supports such files. All of the listed programs support CDL files, but may vary in offered function and purpose. Some programs may be capable only of viewing contents of CDL files or offer file conversion options, but may not be capable of editing such files.
It is possible that although a compatible program has been installed on user’s system, it is not used by the system to open it. This may happen because no default application was associated with this type of files. To associate CDL files with given application, select "Open with" from drop-down menu (accessed by right-clicking on the file). Then select from the list the program or application you want to be used to open this type of file. If the CADKEY Wireframe applications is not on the list, select "Browse" option in order to manually locate the directory where CADKEY Wireframe has been installed.
Sometimes problems with opening CDL files may not lie with the application itself, but can arise due to other causes, such as: