We have calculated a grid of solar abundance model atmospheres. In addition, we have calculated grids with metallicities , -0.5 and -0.7 to facilitate comparison to observed LMC and SMC giants. The models span a range of and . The models are not available for all combinations of these parameters, e.g., at high and low the total radiative acceleration is larger than the local gravity and hydrostatic models become invalid. In order to minimize CPU time, the models were calculated for a fixed mass of . In the following, we discuss the effects of different model parameters on the resulting structures and spectra. The effects of the model parameters on the colors are discussed in the context of evolutionary models by .