The behavior of fabric structures and of coated and uncoated fabric material under different loading conditions, prestress, snow and wind loads is described in general terms. The paper tries to explain some of the characteristics of fabric behavior using a triangular truss model that was originally proposed by Mef fert in 1978 for PVC-coated polyester fabric; the model has been modified to include slack-elastic material behavior. The limitations of this model are discussed, and a case is argued for a simple and adequate fabric model. To determine the required fabric parameters from simple tests, a possible strategy is outlined. Some reference is made to the current state of knowledge on the shear stiffness of coated fabrics and the need for more detailed studies is stated.