  We study the nature of motion in a 3D potential composed of perturbed
elliptic oscillators. Our technique is to use the results obtained from the 2D
potential in order to find the initial conditions generating regular or chaotic
orbits in the 3D potential. Both 2D and 3D potentials display exact periodic
orbits together with extended chaotic regions. Numerical experiments suggest,
that the degree of chaos increases rapidly, as the energy of the test particle
increases. About 97% of the phase plane of the 2D system is covered by chaotic
orbits for large energies. The regular or chaotic character of the 2D orbits is
checked using the S(c) dynamical spectrum, while for the 3D potential we use
the S(c) spectrum, along with the P(f) spectral method. Comparison with other
dynamical indicators shows that the S(c) spectrum gives fast and reliable
information about the character of motion.
