  We demonstrate that gamma-ray burst afterglow spectra and light curves can be
calculated for arbitrary explosion and radiation parameters by scaling the peak
flux and the critical frequencies connecting different spectral regimes. Only
one baseline calculation needs to be done for each jet opening angle and
observer angle. These calculations are done numerically using high-resolution
relativistic hydrodynamical afterglow blast wave simulations which include the
two-dimensional dynamical features of expanding and decelerating afterglow
blast waves. Any light curve can then be generated by applying scaling
relations to the baseline calculations.
  As a result, it is now possible to fully fit for the shape of the jet break,
e.g. at early time X-ray and optical frequencies. In addition, late-time radio
calorimetry can be improved since the general shape of the transition into the
Sedov-Taylor regime is now known for arbitrary explosion parameters so the
exact moment when the Sedov-Taylor asymptote is reached in the light curve is
no longer relevant.
  When calculating the baselines, we find that the synchrotron critical
frequency and the cooling break frequency are strongly affected by the jet
break. The synchrotron break temporal slope quickly drops to the steep late
time Sedov-Taylor slope, while the cooling break first steepens then rises to
meet the level of its shallow late time asymptote.
