Planning construction projects typically makes use of the activity network based Critical Path Method (CPM), since it is very simple to use and reasonably versatile. Most other planning techniques are either aimed at specialized types of construction work (such as linear scheduling techniques) or are peripheral tools to be used in conjunction with these tools (such as n-D CAD). Discrete-event simulation has also been used for construction planning, and while it is extremely versatile, it lacks the simplicity in use of CPM and so has not been widely adopted within the industry. This paper goes back to first principles, identifying the needs of construction project planning and how existing tools meet (or fail to meet) these requirements. Based on this, it proposes a new modeling paradigm better suited to contemporary construction project planning. The principles of the method are demonstrated with a range of examples from construction.