Uncertainties in design solutions are a function of object complexities. So as to deal with such uncertainties, characterization of each solution space and management of uncertainties are required to reach a solution, where main concerns focused on boundaries of solution spaces. Differences between uncertainties of measurements and uncertainties in design are in the order of data and models, namely, models antedate data corresponding alternatives in design and models postdate data implying reactive explanations for data. This consequent feature in design requires management of shortage of information and/or mixing of different mechanisms due to the inherent attribute of models. Observations on boundaries of solution spaces focusing on structural attributes are summarized to give a starting point for management of uncertainties in design.