This program was inspired by this post on /r/gamedev.
The technique described here not only looks nice, but allows you to do voxel graphics in purely 2D engines (as long as you can do matrix transformations).
The big downside is that it is an absolute PITA to create assets for, because you need to draw your voxel object layer-by-layer by hand.

To make this a lot easier I decided to write this program.
It takes a MagicaVoxel .vox file, and creates a .png sprite sheet from it. To show you what I mean by that, here are some screenshots:

Source model: Resulting sprite sheet:

// TODO Add an in engine screenshot here

Vox2png doesn't have any dependencies except the C Standard Library (and math.h). Just compile vox2png.c with your C compiler, like this:

gcc vox2png.c -o vox2png -lm

Then you just run it like this:

./vox2png input.vox output.png

Or, if you want to use a special sprite packing mode use this:

./vox2png input.vox output.png horizontal/vertical/square

There is also a mode that gives each sprite cell its own png file:

./vox2png input.vox output multifile

Which produces numbered files for each Z layer, like this: output0.png, output1.png .. outputN.png

If you want to see a certain feature, just ask me and I'll add it. Or, if you know C, it shouldn't be hard to do it yourself.