In solid freeform fabrication processes that make use of a removable support material, pre-calculation of the amount of support material needed for a build is difficult (inaccurate or slow) because the digital data for generating the support material is often not generated until the build is in progress. A method is proposed that has been shown to generate rapid and accurate estimates of the amount of both build and support material needed before a build begins, to accurately predict before a build begins when replenishment materials are needed, and to track material consumptions over time.