An actual machining center specification, e.g. the axes travel, the workpiece size allowance, etc.; needs to be considered for constructing a machining process plan. In this paper, a machinable space of a five-axis machining center is proposed for simulating the workpiece setup. The machinable space is constructed by a table region and a tool cone. The tool cone is an allowance of the spindle diameter and the cutting tool length. By fitting in the visibility area from a total removal volume (TRV) of the machining process plan, a TRV network can be established. The workpiece setup is estimated by positioning the TRV network within the table region. The positioning process can be used for estimating the number of setup changes on the corresponding machinable space. © 2014 Published by Elsevier B.V.