We present MeepSAT (MEEP Simulation and Analysis for Telescopes), an ongoing project at
the University of Iceland to develop a Finite-Difference-Time-Domain (FDTD) simulation
framework  (based on MEEP) for studying systematics of the full optics tube of CMB
Telescopes. MeepSAT will allow us to simulate the systematic effects caused by features
that current industry-standard optics softwares, such as ZEMAX, CST, and GRASP, are
unable to model for the entire telescope system (for e.g., features such as Absorbers,
ARCs, Forebaffles etc). Variation in the sensitivity of the telescope due to material
properties, detector loading, optimising absorbers and forebaffles and modelling thermal
emissions from different instruments are some of the key science goals of this tool. In
this talk, I will explain about the capabilities of MeepSAT and discuss the recent
progress of the project, mainly used to simulate the Taurus balloon borne system and
SO-SAT. I will conclude the talk by mentioning its potential usage for LiteBIRD.