accomplished in several ways depending on the nature of the material and priorities of the user according to the preferred embodiment some materials are prompted for selection and then incorporated into the graphical model and cost estimate model other types of materials are selected automatically for the user in a quantity determined by the specifications of the building plans and incorporated into the graphical model and cost estimate model materials that have a considerable effect on the overall aesthetics of the house such as carpeting tile wall paper trim aluminum siding and exposed brick are prompted for selection in the prompt window fig4 illustrates such a prompt for phase 8 wall and floor coverings step 2 install floor covering the user has selected main floor dining room in the graphical model window which at this point is blank the prompt u201c select floor covering for main floor dining room u201d is displayed in a top section of prompt window a list of competing local suppliers is displayed in a lower left section of the prompt window and the supplier u201c floors 4u u201d is highlighted product data for floor covering products offered by floors 4u are displayed in lower right section of the prompt window the product data includes the name of the product the cost per unit and a digital image of the product upon the user selecting the desired floor covering the user computer applies the selected floor covering.