  Voxel-based soft robots (VSRs) are aggregations of soft blocks whose design
is amenable to optimization. We here present a software, 2D-VSR-Sim, for
facilitating research concerning the optimization of VSRs body and brain. The
software, written in Java, provides consistent interfaces for all the VSRs
aspects suitable for optimization and considers by design the presence of
sensing, i.e., the possibility of exploiting the feedback from the environment
for controlling the VSR. We experimentally characterize, from a mechanical
point of view, the VSRs that can be simulated with 2D-VSR-Sim and we discuss
the computational burden of the simulation. Finally, we show how 2D-VSR-Sim can
be used to repeat the experiments of significant previous studies and, in
perspective, to provide experimental answers to a variety of research
questions.
