matplotlib

px.Plot draws with matplotlib by default and returns the matplotlib Axes, so titles, panels, annotations and saving work as in any other matplotlib figure. Passing an Axes as ax draws into it, which puts several objects into one figure or into the panels of plt.subplots. Besides faces, shapes, wires, compounds and sketches, Plot takes selections, ids such as "Sketch.1", and OpenCASCADE shapes.

The example on this page is a bell crank: a pivot boss of radius 9 and two arms, 40 and 30 long, that end in bosses of radius 6, with a hole in each boss. Each arm is a line offset by 4, which gives a band of width 8 with round ends.

import matplotlib.pyplot as plt
import planex as px

bosses = [px.Circle((0, 0), 9).Face(), px.Circle((40, 0), 6).Face(), px.Circle((0, 30), 6).Face()]
arms = [px.Line((0, 0), (40, 0)).Offset(4), px.Line((0, 0), (0, 30)).Offset(4)]
holes = [px.Circle((0, 0), 4).Face(), px.Circle((40, 0), 3).Face(), px.Circle((0, 30), 3).Face()]
crank = px.Subtract([px.Unify(bosses + arms), *holes])

Two positions in one figure

The example draws the bell crank at rest and swung by 30° about its pivot. The second call draws into the Axes that the first call returned, and each position gets its own fill color.

ax = crank.Plot(face_col="lightsteelblue", legend=False)
crank.Rotated((0, 0), 30).Plot(ax=ax, face_col="wheat", legend=False)
ax.set_title("Bell crank at 0° and 30°");

Panels: before and after fitting arcs

With line_col="type", lines are drawn in black, arcs in orange and splines in green, each with a legend entry. This shows what a defeaturing step did. The example is a slot as it might come from a tessellated export: the exact slot, of width 2 along a spine of 4, is turned into a polygon with Polylines, and FromPolyline makes a wire of short lines from it. FitArcs turns the short lines back into the slot’s two lines and two arcs. The two panels of plt.subplots show the polygon and the fitted slot side by side.

exact = px.QuickSketch((-2, 0)).Slot(4, 2).Face()
slot = px.Face([px.FromPolyline(exact.Polylines(1e-3)[0], closed=True)])
fitted = slot.Copy().FitArcs(tol=1e-4, max_edge_length=0.2)

fig, (left, right) = plt.subplots(1, 2, figsize=(12, 3))
slot.Plot(ax=left, line_col="type", face_col=None, legend=False)
fitted.Plot(ax=right, line_col="type", face_col=None)
left.set_title(f"{len(slot.edges)} edges")
right.set_title(f"Fitted: {len(fitted.edges)} edges");

See Fitting arcs for the fit and its tolerance.

A section through a solid

With a plane as the second argument, px.Plot draws the section of an OpenCASCADE shape in that plane. The example is a block of 60 × 40 × 20 with a bore of diameter 16 and a step milled into one end, cut at half its height. px.Intersect3d returns the same section as a planex2d shape, for measuring it or for further Boolean operations.

import netgen.occ as occ

block = occ.Box(occ.Pnt(0, 0, 0), occ.Pnt(60, 40, 20)) - occ.Cylinder(occ.Pnt(20, 20, 0), occ.Z, 8, 20)
block = block - occ.Box(occ.Pnt(35, 10, 8), occ.Pnt(60, 30, 20))
px.Plot(block, px.XY.Offset(10));

The look of these docs

The figures in this documentation are drawn the same way, with one color for every edge, a light fill and no axes:

ax = crank.Plot(line_col="#22303c", face_col="#dde6f0")
ax.axis("off");

Saving

ax.figure is the matplotlib figure, so it is saved as any other:

ax = crank.Plot()
ax.figure.savefig("bell-crank.png", dpi=200)