Scalar Quantities

Visualize scalar (real or integer)-valued data at the elements of a surface mesh.


import numpy as np
import polyscope as ps

N_vert = 100
N_face = 250
vertices = np.random.rand(N_vert, 3) # (V,3) vertex position array
faces = np.random.randint(0, N_vert, size=(N_face,3)) # (F,3) array of indices 
                                                      # for triangular faces

ps_mesh = ps.register_surface_mesh("my mesh", vertices, faces)

# visualize some random data per-vertex
vals_vert = np.random.rand(N_vert)
ps_mesh.add_scalar_quantity("rand vals", vals_vert, enabled=True)

# visualize some random data per-face
vals_face = np.random.rand(N_face)
ps_mesh.add_scalar_quantity("rand vals2", vals_face, defined_on='faces')

# visualize some random data per-edge (halfedges are also supported)
vals_edge = np.random.rand(ps_mesh.n_edges())
ps_mesh.add_scalar_quantity("rand vals3", vals_edge, defined_on='edges')

# as always, we can customize the initial appearance
ps_mesh.add_scalar_quantity("rand vals3 opt", vals_edge, defined_on='edges', 
                            enabled=True, vminmax=(-3., 3.), cmap='reds')

# view the mesh with all of these quantities 

SurfaceMesh.add_scalar_quantity(name, values, defined_on='vertices', enabled=None, datatype="standard", vminmax=None, cmap=None)

Add a scalar quantity to the mesh.

  • name string, a name for the quantity
  • values a length N numpy array, scalars at vertices/faces/etc
  • defined_on one of 'vertices','faces','edges','halfedges', is this data a value per vertex or a value per face, etc?

Additional optional keyword arguments:

  • enabled boolean, whether the quantity is initially enabled (note that generally only one quantity can be shown at a time; the most recent will be used)
  • datatype one of standard, symmetric, or magnitude, affects default colormap and map range
  • vminmax a 2-tuple of floats, specifying the min and max range to colormap in to
  • cmap string, which colormap to use

if not specified, these optional parameters will assume a reasonable default value, or a persistent value if previously set.