grid lines about gr HOT 5 CLOSED

Do you have an image of what you are trying to achieve? gr3.createsurfacemesh would used be for creating a surface plot. A "rectangular grid of lines" sounds more like something built from cylinders (and possibly spheres for the corners) like this:

import gr3
import numpy as np

n_per_axis = 11
n = 2*n_per_axis
positions = np.zeros((n, 3))
positions[:n_per_axis, 0] = np.linspace(-2, 2, n_per_axis)
positions[:n_per_axis, 1] = -2
positions[n_per_axis:, 0] = -2
positions[n_per_axis:, 1] = np.linspace(-2, 2, n_per_axis)
directions = np.zeros((22, 3))
directions[:n_per_axis, 1] = 1
directions[n_per_axis:, 0] = 1
colors = np.ones((22, 3))
radii = 0.01 * np.ones(22)
lengths = 4 * np.ones(22)

gr3.drawcylindermesh(n, positions, directions, colors, radii, lengths)
gr3.export("grid.png", 1000, 1000)

As an aside: 0 * gr3.GR3_SurfaceOption.GR3_SURFACE_FLAT is equal to 0 and therefore gr3.GR3_SurfaceOption.GR3_SURFACE_DEFAULT.

from gr.

thanks! this looks like what i would like to achieve. i did not think of the cylinder option - i was considering that there must be some sort of 'line' primitive also in 3D with a constant width. the surface plot functions must also use something like that to draw the mesh, no? would a surface plot of a constant-zero function not also work?

the 0 * .. bit was a quick test that i mistakenly copied-and-pasted.

from gr.

GR3 does not support 2D primitives like points and lines, so cylinders or cuboids would be the way to go for a grid. The gr3_createsurfacemesh function creates a 3D mesh based on the x, y and z arrays.

from gr.

i think i misunderstood what gr3_createsurfacemesh does. i thought it generates a wireframe-like surface representation. but instead it generates a surface mesh which is rendered as a solid surface -- correct?

from gr.

Correct. Together with functions like gr3.surface and gr3.drawsurface it serves as somewhat of an equivalent to gr.surface.

from gr.