MissionComputer is a software application developed by David Arthur for Mac OS 9 and X. It provides plug-in developers with a convenient tool to create and modify Nova resource files in both the Npïf and .rez file formats and can handle all standard Nova resource types. MissionComputer incorporates two other tools by the author: Mac Plug-in Convertor and EV Nova Target Generator. By using a standard, modern user interface and focusing on Nova-specific resources, MC is far more convenient for plug-in development than general-purpose tools such as ResEdit.
Here is a screenshot from the Mac OS X (Tiger) version of MC:
MissionComputer can be downloaded free of charge from here: