Thatched grass based rooves are a wisdom of Asia. They have been used on many kinds of accommodation and for decoration such as tiled rooves, walls etc. Nowadays, computer graphics are involved in many applications. For example, computer games, VR (Virtual Reality) and simulation. These kinds of applications try to simulate a thatched grass based roof as an aesthetic virtual scene for a user. However, the realistics of thatched grass based rooves were ignored. The characteristics were not based on physical appearance.