Transparent surface plots

[dpsanders]

The alpha parameter seems to have no effect for surface plots.

e.g. this example from the NLSolve.jl README:

f(x, y) = ((x+3)*(y^3-7)+18, sin(y*exp(x)-1))

surface(-5:0.05:5, -5:0.05:5, (x,y)->f(x,y)[1], alpha=0.5, zlim=(-2, 2))
surface!(-5:0.05:5, -5:0.05:5, (x,y)->f(x,y)[2], alpha=0.5)

(which shows that there is a continuum of solutions, by the way).

[sglyon]

Yeah, in this case you are looking for opacity, not alpha.

See docs here https://plot.ly/javascript/reference/#surface-opacity

[sglyon]

Hmm, it looks like this isn't even valid code for PlotlyJS.jl

Are you using Plots.jl to create the surface?

Here's an example from this package's docs that has opacity in a surface:

function multiple_surface()
    z1 = Vector[[8.83, 8.89, 8.81, 8.87, 8.9, 8.87],
                [8.89, 8.94, 8.85, 8.94, 8.96, 8.92],
                [8.84, 8.9, 8.82, 8.92, 8.93, 8.91],
                [8.79, 8.85, 8.79, 8.9, 8.94, 8.92],
                [8.79, 8.88, 8.81, 8.9, 8.95, 8.92],
                [8.8, 8.82, 8.78, 8.91, 8.94, 8.92],
                [8.75, 8.78, 8.77, 8.91, 8.95, 8.92],
                [8.8, 8.8, 8.77, 8.91, 8.95, 8.94],
                [8.74, 8.81, 8.76, 8.93, 8.98, 8.99],
                [8.89, 8.99, 8.92, 9.1, 9.13, 9.11],
                [8.97, 8.97, 8.91, 9.09, 9.11, 9.11],
                [9.04, 9.08, 9.05, 9.25, 9.28, 9.27],
                [9, 9.01, 9, 9.2, 9.23, 9.2],
                [8.99, 8.99, 8.98, 9.18, 9.2, 9.19],
                [8.93, 8.97, 8.97, 9.18, 9.2, 9.18]]
    z2 = map(x->x+1, z1)
    z3 = map(x->x-1, z1)
    trace1 = surface(z=z1, colorscale="Viridis")
    trace2 = surface(z=z2, showscale=false, opacity=0.9, colorscale="Viridis")
    trace3 = surface(z=z3, showscale=false, opacity=0.9, colorscale="Viridis")
    plot([trace1, trace2, trace3])
end

[dpsanders]

Ah yes, sorry, using Plots.jl.
Can Plots.jl just translate alpha to opacity?

[sglyon]

It looks like alpha and opacity are synonyms in plots.jl: https://github.com/JuliaPlots/Plots.jl/blob/cadb0f96e2adc1fe749e46998bd78e8da7c133e9/src/args.jl#L412

But by doing a quick search over opacity in the plotly backend it doesn't appear to be used: https://github.com/JuliaPlots/Plots.jl/blob/master/src/backends/plotly.jl

I'll close here as it seems to be an issue over there. Should be easy enough for them to fix.