Both individual weapons and deployable weapons are pre-defined game elements that have been developed by Novaquark. There are currently no plans to create a voxel editor to develop character weapons. At the moment, character weapons are planned to be mesh-based, and defined by developers. It is possible that something to allow players to create their own weapons will be implements eventually, but this would be in the far future of development.  If players were to make their own weapons, then a devoted 3D modeler would be required geared specifically towards Dual Universe, which would take a tremendous amount of development time.