  The spatial and temporal characteristics of particle emitting source produced
in particle and/or nuclear collisions can be measured by using two-particle
femtoscopic correlations. These correlations arise due to quantum statistics,
Coulomb and strong final state interactions. In this paper we report on the
calculations of like-sign pion femtoscopic correlations produced in p+p, p+Au,
d+Au, Au+Au at top RHIC energy using Ultra Relativistic Quantum Molecular
Dynamics Model (UrQMD). Three-dimensional correlation functions are constructed
using the Bertsch-Pratt parametrization of the two-particle relative momentum.
The correlation functions are studied in several transverse mass ranges. The
emitting source radii of charged pions, Rout , Rside , Rlong , are obtained
from Gaussian fit to the correlation functions and compared to data from the
STAR and PHENIX experiments.
