Raisim can be fully deterministic given the contact solver iteration order.
This order can be set by
Determinism is important because of the two reasons. First, determinism allows you to control stochasticity of simulation yourself. This makes many sampling-based stochastic optimal control methods possible. Second, determinism often means bug-free reliable simulation. Non-deterministic simulation is often caused by unintended memory read/write. It is very unlikely that programmers of a simulator intentionally implemented stochasticity in simulation. There are very few exceptions, such as stochastic contact solvers, but they are very rare.