We address the model acquisition problem for an unknown planar polygonal terrain by a team of two or three point robots. The robots are equipped with visual sensors which acquire all visible parts of the terrain by scan operations executed from their locations. The robots communicate with each other via wireless connection. The performance is measured by the number of the sensor (scan) operations. We employ the restricted visibility graph methods an a hierarchical setup. For terrains with convex obstacles and for teams of n (where n=2, 3) robots, we prove that the sensing time is reduced by a factor of 1/n. For terrains with concave corners, the performance of the algorithm for the n(2, 3) robot team is expressed in terms of the sizes of n-connected components, and the sizes and diameters of (n-1) or less connected components.