Non uniform grid for volume plots

[Luluser]

Documentation gives :

volume(volume_data)
volume(x, y, z, volume_data)

Plots a volume with optional physical dimensions x, y, z.

But x,y,z seem to be only used for their boundaries and now warns :
Using an AbstractVector to specify one dimension of an ImageLike is deprecated because ImageLike sides always need exactly two values, start and stop.
Use interval notation start .. stop or a two-element tuple (start, stop) instead.

Hence it is not possible to have voxels of different sizes even for highly structured grids such as rectilinear grids with monotonically increasing spacing.

It would be really nice to have the interpolation of voxels based on the abstract vectors given in x,y,z directly in the method but I am well unable to rewrite the shader primitive.