  This paper aims to track the 3D evolution of a full halo CME on 2011 June 21.
The CME results from a non-radial eruption of a filament-carrying flux rope in
NOAA active region 11236. The eruption is observed in EUV wavelengths by the
EUVI on board the ahead and behind STEREO spacecrafts and the AIA on board SDO.
The CME is observed by the COR1 coronagraph on board STEREO and the C2
coronagraph on board SOHO/LASCO. The revised cone model is slightly modified,
with the top of the cone becoming a sphere, which is internally tangent to the
legs. Using the multi-point observations, the cone model is applied to derive
the morphological and kinematic properties of the CME. The cone shape fits
nicely with the CME observed by EUVI and COR1 on board STEREO twin spacecraft
and LASCO/C2 coronagraph. The cone angle increases sharply from 54$^{\circ}$ to
130$^{\circ}$ in the initial phase, indicating a rapid expansion. A relation
between the cone angle and heliocentric distance of CME leading front is
derived, $\omega=130\degr-480d^{-5}$, where $d$ is in unit of $R_{\odot}$. The
inclination angle decreases gradually from $\sim$51$^{\circ}$ to
$\sim$18$^{\circ}$, suggesting a trend of radial propagation. The heliocentric
distance increases gradually in the initial phase and quickly in the later
phase up to $\sim$11\,$R_{\odot}$. The true speed of CME reaches $\sim$1140 km
s$^{-1}$, which is $\sim$1.6 times higher than the apparent speed in the
LASCO/C2 field of view. The revised model is promising in tracking the complete
evolution of CMEs.
