Split a DXF drawing by layer

Use the .cad accessor to fan a single pyvista.PolyData back out into a pyvista.MultiBlock keyed by layer name. Each block contains only the cells originally drawn on that layer.

This example uses a real multi-layer DXF from the ezdxf project (MIT) with entities on layers 0, BLUE, RED, so the layer split is non-trivial, exactly what you face on a real PCB or architectural DXF.

import pandas as pd
import pyvista as pv

import pyvista_cad
from pyvista_cad.examples import downloads

Read the real drawing.

drawing = pyvista_cad.read_dxf(downloads.dxf_drawing_path())
drawing

PolyData (0x7f6faa75cdc0)
  N Cells:    68
  N Points:   710
  N Strips:   0
  X Bounds:   4.001e+01, 1.750e+02
  Y Bounds:   6.339e+01, 1.254e+02
  Z Bounds:   0.000e+00, 0.000e+00
  N Arrays:   7

PolyData 710 points 68 cells 32 KiB

Bounds⧉X [4.001e+01, 1.750e+02]Y [6.339e+01, 1.254e+02]Z [0.000e+00, 0.000e+00]

Cellslines 68

• Cell Data: (2)
  • Layer⧉
    scalar
    <U4
  • cad.layer⧉
    scalar
    <U4
• Field Data: (5)
  • cad.source_format⧉
    (1,)
    <U3
  • cad.reader⧉
    (1,)
    <U20
  • cad.backend⧉
    (1,)
    <U5
  • cad.source_format_version⧉
    (1,)
    <U5
  • cad.units⧉
    (1,)
    <U4

Split by layer. Each child PolyData keeps the cad.layer cell-data array so further reshuffles round-trip.

by_layer = drawing.cad.split_by_layer()
pd.DataFrame(
    [
        {'layer': name, 'cells': block.n_cells}
        for name, block in zip(by_layer.keys(), by_layer)
        if block is not None
    ]
)

	layer	cells
0	0	44
1	BLUE	12
2	RED	12

Render each layer with its own color so the drawing’s logical structure is immediately visible.

pl = pv.Plotter()
palette = ['steelblue', 'indianred', 'goldenrod', 'mediumseagreen', 'orchid', 'slategray']
for i, (name, block) in enumerate(zip(by_layer.keys(), by_layer)):
    if block is None or block.n_cells == 0:
        continue
    pl.add_mesh(block, color=palette[i % len(palette)], line_width=2, label=str(name))
pl.add_legend()
pl.view_xy()
pl.show()

Static Scene

Interactive Scene