Here’s a solution using Makie:
using GLMakie
x = 0:0.05:3;
y = 0:0.05:3;
z = @. sin(x) * exp(-(x+y))
fig = Figure(size=(400, 300))
ax = Axis3(fig[1,1], limits=((0,3), (0,3), (0,0.2)),
azimuth=0.3, elevation=0.4)
lines!(Point3f.(x, 0, z))
lines!(Point3f.(0, y, z))
band!(Point3f.(x, y, 0), Point3f.(x, y, z), color=(:red, 0.5))
fig
I used GLMakie because CairoMakie handles the transparency poorly for some reason:
