Describe a sphere for mesh tag assignment.
- Args:
- radius : float, optional
- Radius of the sphere, defaults to 0
- centre : array-like, optional
- Centre of the sphere, defaults to (0,0,0)
- tag : int, optional
- Tag ID to assign to this region, defaults to auto assign by mesher
- bath : int, optional
- 0 - no bath, 1 - isotropic bath, 2 - anisotropic bath, default is 0