add_vertex_data

Mesh.add_vertex_data(name, attr, data, default=None)[source]

Add vertex data.

The data object has to allow access to vertex data using index notation. The data block as a whole can be accessed via self.name and the value data[v] as v.attr.

Parameters:

  • name (str) – Name of the data block.

  • attr (str) – Name of vertex attribute.

  • data (list or dict or ndarray) – Data object.

  • default (object, optional) – Immutable default vertex attribute value.

Raises:

ValueError – If a data block of the same name already exists.

To add a vector field (one vector per vertex) to a mesh we can do the following:

 1 # Allocate data block of appropriate size and type.
 2 vecs = np.array_like(mesh.points)
 3
 4 # Compute values for each vertex of the mesh.
 5 for v in mesh.vertices:
 6     vecs[v] = ...
 7
 8 # Add the data block to the mesh. The vecs array can now be
 9 # accessed as mesh.vecs (we could have used any other name).
10 mesh.add_vertex_data('vecs', 'vec', vecs)
11 print(mesh.vecs is vecs)
12
13 # Rows of the data block can now be accessed locally just
14 # like the rows of the vertex coordinate array.
15 for v in mesh.vertices:
16     print(v.vec == vecs[v])

Note

A mutable default value has the same drawbacks as mutable default function arguments.