This is the first of a set of papers having the aim to provide a detailed
description of brane configurations on a family of noncompact threedimensional
Calabi–Yau manifolds. The starting point is the singular
manifold defined by a given quotient $C3/Z6$, which we called simply $C^3_6$
and which admits five distinct crepant resolutions. Here we apply local
mirror symmetry to partially determine the prepotential encoding the
$GW$-invariants of the resolved varieties. It results that such prepotential
provides all numbers but the ones corresponding to curves having null
intersection with the compact divisor. This is realized by means of a conjecture,
due to S. Hosono, so that our results provide a check confirming
at least in part the conjecture.