Plot ellipsoids with Mayavi

Hi. I wanted to plot 3D ellipsoids with Mayavi. I got the following script

from enthought.mayavi.api import Engine
from enthought.mayavi.sources.api import ParametricSurface
from enthought.mayavi.modules.api import Surface
from enthought.mayavi import mlab

import numpy as np

engine = Engine()
engine.start()
scene = engine.new_scene()
scene.scene.disable_render = True # for speed

surfaces = []
for i in range(10):

    source = ParametricSurface()
    source.function = 'ellipsoid'
    engine.add_source(source)

    surface = Surface()
    source.add_module(surface)

    actor = surface.actor # mayavi actor, actor.actor is tvtk actor
    #actor.property.ambient = 1 # defaults to 0 for some reason, ah don't need it, turn off scalar visibility instead
    actor.property.opacity = 0.5
    actor.property.color = tuple(np.random.rand(3))
    actor.mapper.scalar_visibility = False # don't colour ellipses by their scalar indices into colour map
    actor.property.backface_culling = True # gets rid of weird rendering artifact when opacity is < 1
    #actor.property.frontface_culling = True
    actor.actor.orientation = np.random.rand(3) * 360 # in degrees
    actor.actor.origin = np.random.rand(3)
    actor.actor.position = np.random.rand(3)
    actor.actor.scale = np.random.rand(3)

    surfaces.append(surface)

scene.scene.disable_render = False # now turn it on

# set the scalars, this has to be done some indeterminate amount of time
# after each surface is created, otherwise the scalars get overwritten
# later by their default of 1.0
for i, surface in enumerate(surfaces):
    vtk_srcs = mlab.pipeline.get_vtk_src(surface)
    print('len(vtk_srcs) = %d' % len(vtk_srcs))
    vtk_src = vtk_srcs[0]
    try: npoints = len(vtk_src.point_data.scalars)
    except TypeError:
        print('hit the TypeError on surface i=%d' % i)
        npoints = 2500
    vtk_src.point_data.scalars = np.tile(i, npoints)

# on pick, find the ellipsoid with origin closest to the picked coord,
# then check if that coord falls within that nearest ellipsoid, and if
# so, print out the ellispoid id, or pop it up in a tooltip

mlab.show()

I found that I cannot visualize my ellipsoids with this script, because I do not understand the meaning of some commands/functions.

My data included: the center of ellipsoids, vectors of three principal axes, and the lengths of three axes.

But, as one can see in the script, the input parameters of the script are

    actor.actor.orientation = np.random.rand(3) * 360 # in degrees
    actor.actor.origin = np.random.rand(3)
    actor.actor.position = np.random.rand(3)
    actor.actor.scale = np.random.rand(3)

The origin might be the center of ellipsoids. But I do not understand orientation, position, and 'scale'?

How can I generate my ellipsoids with these functions? Can someone help me? thanks in advance.

enthought / mayavi

Plot ellipsoids with Mayavi #1191