Hermite data structure/generation

Hey everybody,
I am working on a voxel engine for java and decided to go for the Cubical Marching Squares method. It uses Hermite Data to detect sharp features and solve cracks in adaptive grids.
My problem is I am not quite sure how to structure it and generate it from a density field. Has anyone worked with that kind of data yet and could help me out with that?

Enter “marching cubes” in the search field up right.

@normen said: Enter "marching cubes" in the search field up right.

yea i did that but that didn’t really help me. I don’t have problems with the extraction method in general but only how the hermite data fits into all this. Actually this article clears up some things but still I am not sure how the quads he mentions look like or which vertices he actually connects.