pyvista_wasm.PolyData.contour

pyvista_wasm.PolyData.contour#

PolyData.contour(isosurfaces: int | list[float] = 10, scalars: ArrayLike | None = None, scalar_name: str | None = None) → PolyData#

Generate contour lines at constant scalar values.

This filter extracts isolines from the mesh at specified scalar values using a marching triangles algorithm implemented in JavaScript. It mirrors the PyVista contour filter API. The contour is computed at render time as a manual implementation because vtkContourFilter is not registered with the vtkDeserializer in VTK.wasm’s rendering-mode binary.

Parameters:

  • isosurfaces (int or list of float, optional) – Number of evenly spaced contours to generate, or a list of explicit scalar values at which to generate contours. Default is 10.

  • scalars (array-like, optional) – Scalar values per point to use for contouring. If not provided, uses the mesh’s existing scalars attribute. Must have length equal to n_points.

  • scalar_name (str, optional) – Name for the scalar array in VTK.wasm. If not provided, uses the mesh’s existing scalar_name attribute or defaults to “scalars”.

Returns:

A new mesh containing the contour lines.

Return type:

PolyData

Raises:

ValueError – If no scalars are provided and the mesh has no scalar data, or if isosurfaces parameter is invalid.

Examples

>>> import pyvista_wasm as pv
>>> sphere = pv.Sphere()
>>> sphere_scalars = sphere.points[:, 2]
>>> contours = sphere.contour(isosurfaces=5, scalars=sphere_scalars)
>>> isinstance(contours, pv.PolyData)
True

Generate contours at specific values:

>>> contours = sphere.contour(isosurfaces=[-0.5, 0.0, 0.5], scalars=sphere_scalars)

Render the contours:

>>> contours.plot()