In this work, the need of the CAD systems of making available to the user means of manipulating the created solid models in a more flexible way is emphasized. It will be showed the historical evolution of these systems and the growing need of models capable to represent a larger volume of information and manipulate them consistently. The parametric and variational methodologies come as a good option for the consistent and automatic manipulation of changes imposed by the designer, supporting the interactive nature of a product development process. The importance of the sequence of operations adopted by the designer when defining the computational model is verified and two functions, UNDO and REDO, were identified as necessary for a satisfactory manipulation of solid models in CAD systems based on the history of operations execution. For a consistent support to these functions, it is necessary the maintenance of dependency information among the executed operations. The ATMS (Assumption-based Truth Maintenance System) is used as a structure to store the information of necessary dependencies. Basic concepts on Solid Modeling will be presented. The proposal of this work is to present a representation of the dependencies among operations of CAD systems that support Boolean Operations. To achieve this, it will be used two important concepts: Base Solid and Relative Dimensions. A prototype was developed and experimental results are presented.