Can I apply a ColorFunction to FaceGrids, or otherwise have FaceGrids with varying color?

Question

I want to make a 3d plot with FaceGrids with a certain color scheme. Specifically, I'd like them to be one color below a diagonal line, and a different color above it. (So for example, on the y=0 surface, I'd like the FaceGrids to be pink below x=z, and blue above x=z.)

If I were coloring the plot itself, I'd define a ColorFunction, but it seems that FaceGrids doesn't take ColorFunction as an option. Here's an example of my best attempt:

Graphics3D[Cylinder[], 
 FaceGrids -> {{{0, -1, 
     0}, {{{-1/2, ColorFunction -> Function[{x, y, z}, Hue[z]]}, {0, 
       Green}, {1/2, Blue}}, {-1/3, {1/3, 
       Directive[Thick, Dashed]}}}}}]

Note that while the other gridlines have the properties assigned, the one with a ColorFunction is just gray.

Is there any way to have varying colors on FaceGrids?

Answer 1

I don't think it's possible to vary the color along a mesh line. So you'll probably have to do the lines by hand:

Graphics3D[{Cylinder[], Pink, Line[{{-1/2, -1, -1}, {-1/2, -1, 0}}], 
  Blue, Line[{{-1/2, -1, 0}, {-1/2, -1, 1}}]}, 
 PlotRange -> {{-1, 1}, {-1, 1}, {-1, 1}}, 
 FaceGrids -> {{{0, -1, 
     0}, {{{0, Green}, {1/2, Blue}}, {-1/3, {1/3, 
       Directive[Thick, Dashed]}}}}}]

You can apply color functions in a way that varies the color from one line to the next, as shown for MeshStyle in this question. But I don't think that's what you meant.