  We present a program tool, SimClust, designed for Monte-Carlo modeling of
star clusters. It populates the available stellar isochrones with stars
according to the initial mass function and distributes stars randomly following
the analytical surface number density profile. The tool is aimed at simulating
realistic images of extragalactic star clusters and can be used to: (i)
optimize object detection algorithms, (ii) perform artificial cluster tests for
the analysis of star cluster surveys, and (iii) assess the stochastic effects
introduced into photometric and structural parameters of clusters due to random
distribution of luminous stars and non-uniform interstellar extinction. By
applying SimClust, we have demonstrated a significant influence of stochastic
effects on the determined photometric and structural parameters of low-mass
star clusters in the M31 galaxy disk. The source code and examples are
available at the SimClust website: http://www.astro.ff.vu.lt/software/simclust/
