Composite Picking

Demonstrate how to pick individual blocks of a pyvista.MultiBlock using pyvista.Plotter.enable_block_picking().

from __future__ import annotations

import numpy as np

import pyvista as pv

Create a MultiBlock Dataset

Create 100 superellipsoids using pyvista.ParametricSuperEllipsoid()

# Seed rng for reproducibility
rng = np.random.default_rng(seed=0)


def make_poly():
    """Create a superellipsoid in a random location."""
    poly = pv.ParametricSuperEllipsoid(
        n1=rng.random(),
        n2=rng.random() * 2,
        u_res=50,
        v_res=50,
    )
    poly.points += rng.random(3) * 20
    return poly


# Assemble the multiblock and plot it using the default plotting settings
blocks = pv.MultiBlock([make_poly() for _ in range(100)])
blocks.plot()

Static Scene

Interactive Scene

Enable Block Picking

Add blocks to a pyvista.Plotter and enable block picking. For fun, let’s also enable physically based rendering and set the callback to set the block color to red when the block is clicked and unset the color if the color has already been set for the block.

pl = pv.Plotter()
actor, mapper = pl.add_composite(blocks, color="w", pbr=True, metallic=True)


def callback(index, *args):
    """Change a block to red if color is unset, and back to the actor color if set."""
    if mapper.block_attr[index].color is None:
        mapper.block_attr[index].color = "r"
    else:
        mapper.block_attr[index].color = None


pl.enable_block_picking(callback, side="left")
pl.background_color = "w"
pl.show()