  We report on the first multi-color precision light curve of the bright
Wolf-Rayet binary $\gamma^2$ Velorum, obtained over six months with the
nanosatellites in the BRITE- Constellation fleet. In parallel, we obtained 488
high-resolution optical spectra of the system. In this first report on the
datasets, we revise the spectroscopic orbit and report on the bulk properties
of the colliding winds. We find a dependence of both the light curve and excess
emission properties that scales with the inverse of the binary separation. When
analyzing the spectroscopic properties in combination with the photometry, we
find that the phase dependence is caused only by excess emission in the lines,
and not from a changing continuum. We also detect a narrow, high-velocity
absorption component from the He I $\lambda$5876 transition, which appears
twice in the orbit. We calculate smoothed-particle hydrodynamical simulations
of the colliding winds and can accurately associate the absorption from He I to
the leading and trailing arms of the wind shock cone passing tangentially
through our line of sight. The simulations also explain the general strength
and kinematics of the emission excess observed in wind lines such as C III
$\lambda$5696 of the system. These results represent the first in a series of
investigations into the winds and properties of $\gamma^2$ Velorum through
multi-technique and multi-wavelength observational campaigns.
