# Fix mesh grid indexing in 3D dual contouring

I fixed a problem in my previous 3D dual contouring script today.

For a given mesh grid constructed by `numpy.meshgrid`

, for example:

A coordinate of `(x0 + step * x, y0 + step * y, z0 + step * z)`

,
whose integer grid coordinate is `(x, y, z)`

,
needs to be indexed from the mesh grid using `s[y, x, z]`

.

Now the 3D heart function can be successfully contoured:

The source code of this script can be found here. It still has some topology issues to be resolved.