Oh nice, psychophysics with Makie! Well if you use LScene (which is just Scene in a wrapper) you should be able to do LScene(..., scenekw = (show_axis = false,)).
Or you use Axis3 http://makie.juliaplots.org/stable/makielayout/axis3.html, which might have the additional nice property for your experiments that one can’t rotate upside down, and you can’t zoom or pan so the object is always centered. In that case you would do hidedecorations! and hidespines! on the axis. You should probably also set viewmode = :fit so that rotation doesn’t change the apparent size.