Aten is a tool to create, edit, and visualise coordinates. It was written primarily to be of use to people performing simulations of condensed matter, but it may very well be useful to others out there dealing with non-periodic systems.

Amongst other things, Aten can:

	Provide a GUI for editing atomic coordinates
	Create models, even periodic ones, from scratch
	Randomly add in molecules to periodic boxes, allowing disordered systems to be created
	Handle several crystal formats, and can replicate and scale unit cells
	Load and save model data in several model formats out of the box
	Cater for any model format you wish with its Filters system
	Render other primitive object types, as well as surface/gridded data
	Load in vibration/frequency data and animate it
	Be fully scripted / automated from the command line
	Load in and apply forcefield terms to a model with its easy-to-read typing language
	Energy minimise (periodic) models
	Run on Linux, Mac, and Windows

Aten is also completely free.