Grid planar view & parallel projection about pyvista-support

[banesullivan]

@laserman781 - since you posted this twice, once in the main PyVista repo and once here, I'm going to split the two parts of this issue into 1. a question which I'll answer here, and 2. a feature request which I will address in pyvista/pyvista#337

How would I go about having the grid only be shown in the 2d plane (not as a box) at the elevation of the clip?

Simply pass in the bounds of the box you'd like to use - if you want a 2D box, then make the min/max for the plane of no variation the same. For example, in the snippet below, I add a 2D axes grid at the bottom of Mt. St. Helens. All you need to do is specify the bounds argument for show_grid which is a length six array of min/max for each axes (e.g. [xmin,xmax, ymin,ymax, zmin,zmax]).

import pyvista as pv
from pyvista import examples

mesh = examples.download_st_helens().warp_by_scalar()

bounds = mesh.bounds
bounds[5] = bounds[4]

p = pv.Plotter()
p.add_mesh(mesh)
p.show_grid(bounds=bounds)
p.show()

[banesullivan]

FYI: show_grid is an alias/helper for show_bounds - so you might not have seen all the options available unless looking at the docs for show_bounds: https://docs.pyvista.org/plotting/plotting.html#pyvista.BasePlotter.show_bounds