Thank you for bringing up the vtkSkybox example; I wasn’t aware of this solution before. However, when I tried it, I found it quite challenging to control aspects like grid line width, grid spacing (as using values other than powers of 2 creates the appearance of overlapping grids), and fade distance. I rendered both the vtkSkybox (left), my current shader solution (right) examples using the same camera settings with a grid spacing of 10,10, and here is the result.
