Other Scheduling Methods - Construction Project Scheduling and Control - page 320

• For two linked objects, gap measures the extent to which the predecessor may
be delayed and not impact the successor; gap (in this case, drift-gap) also mea-
sures the extent to which the successor may gain schedule and not impact the
predecessor.
• Buffer (equivalent of CPM free float) measures the minimum of the gaps on
logic ties to the activity's successors. It is a GPM-perfected free float concept,
since it homogenizes all relationship types to a single formula.
Unique to GPM is that it continuously updates durations, dates, floats, resource
profiles, and all schedule data on a real-time basis; thus, it eliminates the black-box
mystery behind many CPM applications. This embodies a paradigm shift from CPM
by providing synchronous feedback and an interactive interface that is suited for col-
laborative planning and scheduling. Additionally, GPM is not “early date biased,” as it
allows activities with total float to be scheduled anywhere within the total float range,
focusing on planned dates instead of early dates.
GPM introduces the concepts of proportional link offsets and forensic total float .
Proportional link offsets allow the amount of overlap in a SS, FF, or SF relationship
to be contingent on the duration of the host activity. In many situations, this better
reflects the reality in the field than a more traditional, constant overlap does. In addi-
tion, GPM has the ability to calculate drifts, floats, and therefore total floats left of the
data date , that is, for completed activities. Forensic total floats can be crucial for accu-
rately identifying as-built critical paths, and their calculation facilitates retrospective
delay analysis.
Currently, the only GPM software application available is NetPoint ® .NetPoint
is mathematically based and intuitive to learn and use, making it ideal for scheduling
practitioners and nonscheduling-trained stakeholders alike. This tool allows project
managers, superintendents, subcontractors, and other stakeholders to collaboratively,
in one session, build a schedule by graphically positioning activities on a planning
surface and using a variety of simple and intuitive logic ties to convey relationships.
Development of NetPoint started in 2004 and was commercially released in the fall of
2009. An example of a simple NetPoint schedule is shown in the Figure 11.22. The
histogram at the bottom represents resource profiles in color-coded bars, both in daily
and cumulative formats.
As a collaboration tool, the NetPoint application provides planning, schedul-
ing, resource management, and other project control capabilities that are similar to
what Primavera Project Management and Microsoft Project offer; however, looking
within the software architecture, there exist major differences and enhancements that
underscore how GPM provides a planning-centric, real-time/synchronous, collab-
orative, and intuitive planning environment. Unlike CPM applications anchored in
database-driven scheduling engines that are controlled by a keyboard and mouse, Net-
Point, as an interactive and object-based system, allows hand-directed planning and
scheduling using touch or a stylus.