How to set nan_color in Makie volume plot

Specific Domains Visualization
,
1

I want to set the nan_color to :white or may be :green. How to do it?

using GLMakie
xmin, xmax, ymin, ymax, zmin, zmax = -3, 3, -3, 3, 1, 8;
field = fill(NaN32, 50,50,50);
fig = Figure()
ax::LScene = LScene(fig[1,1])
volume!(ax, xmin..xmax, ymin..ymax, zmin..zmax, field)