branching brownian motion (bbm) is a random particle system where each particle diffuses as brownian motion and branches into a random number of particles at a constant rate. in this talk, we will focus on two variant models of bbm, bbm with absorption and bbm with inhomogeneous breeding potential. in the first model, we derive the long run expected number of particles conditioned on survival in the near critical case. in the second model, we study the entire configuration of particles.