vtk-demo

Fancy VTK / PyVista scenes that show off VTK capabilities and performance: GPU instancing, composite datasets, PBR, transparency, huge point clouds, live simulations… plus the demo applications built on them (VTK.wasm + WebGPU in the browser with trame, standalone HTML exports, and Dear ImGui).

Install

pip install vtk-demo              # scenes only (vtk, pyvista)
pip install "vtk-demo[trame]"     # + web applications
pip install "vtk-demo[export]"    # + standalone HTML export
pip install "vtk-demo[all]"

Reusable scenes

vtk_demo.scenes is plain VTK and numpy, through VTK's Python friendly API (keyword constructors, snake_case properties, numpy backed arrays, >> pipelines). Every build_* function fills a vtkRenderer (actors, background, camera) and returns a few statistics:

import vtkmodules.vtkInteractionStyle  # noqa: F401
import vtkmodules.vtkRenderingOpenGL2  # noqa: F401
from vtkmodules.vtkRenderingCore import (
    vtkRenderer,
    vtkRenderWindow,
    vtkRenderWindowInteractor,
)

from vtk_demo.scenes import build_glyph_island

renderer = vtkRenderer()
n_actors, n_instances, n_triangles = build_glyph_island(renderer)
window = vtkRenderWindow(size=(1280, 800))
window.AddRenderer(renderer)
interactor = vtkRenderWindowInteractor(render_window=window)
interactor.Start()

PyVista only comes in with the applications, through a small adapter that builds a scene into a plotter and keeps the scene's camera:

import pyvista as pv
from vtk_demo.pyvista_adapter import add_scene
from vtk_demo.scenes import build_glyph_island

plotter = pv.Plotter()
n_actors, n_instances, n_triangles = add_scene(plotter, build_glyph_island)
plotter.show()

Module	What it provides
scenes.instancing	InstanceLayer: many copies of one mesh, drawn with a vtkGlyph3DMapper (glyph_actor), one actor per copy (instance_actors) or baked into one mesh (bake_layer)
scenes.composite	composite_actor, scattered_collection, partitioned_collection: many meshes in one vtkCompositePolyDataMapper actor
scenes.island	The 43k object voxel island, drawn four ways: build_glyph_island, build_actor_island, build_archipelago, build_partitioned_island
scenes.pbr	build_pbr_scene: PBR materials and image based lighting
scenes.transparency	build_transparency_scene: depth peeling stress test
scenes.galaxy	build_galaxy_scene: tens of millions of points
scenes.wave	WaveSurface, build_wave_scene: a mesh updated live by a simulation
scenes.isosurface	Isosurface, build_isosurface_scene: live vtkFlyingEdges3D contour
scenes.bunny	build_bunny_scene
scenes.benchmark	build_sphere_mesh, build_sphere_actors: synthetic throughput scenes
scenes.primitives	Shapes (cube, cylinder, cone, arrow, icosphere, super_ellipsoid, trefoil) and textures (stone_tiles_texture, image_texture)
scenes.core	VTK and numpy helpers: mesh_actor, make_property, rgb, lookup_table, vtk_points, transformed, set_camera…
scenes.datasets	bunny, lucy, head, sky_box: example data, downloaded once to ~/.cache/vtk-demo (or $VTK_DEMO_DATA)

Demo applications

vtk-demo list
vtk-demo run trame.glyph            # VTK.wasm on WebGL 2
vtk-demo run trame.glyph --webgpu   # WebGPU in the browser and on the server
vtk-demo run trame.galaxy --help

Without installing anything, uv can run any demo against a VTK of your choice, here a nightly from wheels.vtk.org (-p 0 picks a free port):

uvx --with "vtk>9.7.1" --pre --index-url https://wheels.vtk.org "vtk-demo[trame]" run trame.animation -p 0

Demos are grouped by UI toolkit, under vtk_demo.apps:

• trame: contour, galaxy, animation, pbr, pbr-legacy, transparency, glyph
• export: bunny-html, a self-contained VTK.wasm HTML page
• imgui: contour, the trame contour demo as a native desktop window

Every demo is also a runnable module, e.g. python -m vtk_demo.apps.trame.glyph.

The SimpleViewer based trame demos report first frame and interaction times: see vtk_demo/apps/trame/observability.py (--obs-log, --obs-verbose, --no-hud).

Gallery

Each demo with its default options, VTK.wasm (or vtk.js) on WebGL 2 in Chrome:

trame.contour: isosurface of a CT scan, filtered on the server	trame.galaxy: millions of points with VTK.wasm 64-bit
trame.animation: wave equation stepped in numpy, streamed live	trame.glyph: 43k object voxel island, GPU instancing
trame.pbr: PBR materials and image based lighting	trame.pbr-legacy: the same scene with vtk.js
trame.transparency: depth peeling stress test	export.bunny-html: self-contained HTML page, no server

Notes

• --webgpu also asks the server to render with WebGPU, which needs a VTK built with VTK_ENABLE_WEBGPU=ON; otherwise the server falls back to OpenGL, as shown in the chip when rendering remotely.
• VTK's WebGPU backend has no PBR shaders yet: pbr --webgpu is Phong shaded.
• The uv setup (uv sync, nox, CI) pins a VTK nightly from wheels.vtk.org ([tool.uv] in pyproject.toml): with VTK 9.7.1, VTK.wasm keeps drawing the first frame of trame.animation. pip install vtk-demo uses the latest VTK release instead; to get a nightly with pip: pip install --pre --extra-index-url https://wheels.vtk.org "vtk>9.7.1".

Contributing

See CONTRIBUTING.md for the development setup, how to add a demo and how releases are made.

License

Apache License 2.0