Eternity Engine is a source port, derived from MBF, maintained by James Haley et al. While Eternity is not based on ZDoom, there is collaboration between the developers of both ports to obtain mod compatibility when possible for common features. The Universal Doom Map Format standard is an example of such a collaboration.
When loading an Eternity mod in ZDoom, the -xlat "xlat/eternity.txt" command line parameter can be used. Any Eternity feature that can be currently supported in ZDoom through a map translator will be converted adequately. However, many EE features are not supported and there is no guarantee that the map will be fully playable in this way.