Problem with transparency when I export an eps file

Question

I have the following simple Mathematica code:

Clear["Global`*"];
x = Cos[t];
y = Sin[t];
L1 = ParametricPlot3D[{x, y, t}, {t, 0, 50}, 
   PlotStyle -> {Blue, Thickness[0.003]}, Axes -> True, 
   AxesLabel -> {"x", "y", "t"}, BoxRatios -> {1, 1, 1}, 
   AxesStyle -> Directive[Black, FontSize -> 17, FontFamily -> "Helvetica"], 
   PlotPoints -> 500, PlotRange -> All, ImageSize -> 500];
L2 = Graphics3D[{EdgeForm[None], Opacity[0.2], GrayLevel[0.1], 
Specularity[White, 20], Mesh -> None, Lighting -> None, 
Cuboid[{-1, -1, 38}, {1, 1, 50}]}];
P1 = Show[{L1, L2}, ViewPoint -> {1.3, -2.4, 1.5}] 

However, when I try to export this three-dimensional plot in eps format, all the part of function which is inside the cuboid, that is when z>38 does not appear. It seems that somehow during the export the options Opacity is overruled. Is there a way to export this plot correctly?

Answer 1

If you want to make sure that all exported EPS will look fine even without explicitly rasterizing the plot every time, you can force the rasterization by this one-time command that you could put at the beginning before creating any of your plots:

Map[SetOptions[#, 
    Prolog -> {{EdgeForm[], Texture[{{{0, 0, 0, 0}}}], 
       Polygon[#, VertexTextureCoordinates -> #] &[{{0, 0}, {1, 
          0}, {1, 1}}]}}] &, {Graphics3D, ContourPlot3D, 
   ListContourPlot3D, ListPlot3D, Plot3D, ListSurfacePlot3D, 
   ListVectorPlot3D, ParametricPlot3D, RegionPlot3D, RevolutionPlot3D,
    SphericalPlot3D, VectorPlot3D, BarChart3D}];

The trick is explained in this answer and the linked ones. You're asking about transparency in particular, so I guess it's not quite a duplicate question, but a duplicate answer...

The plots will be rasterized when exporting to PDF or EPS - the notebook internal plots are not rasterized.