Why the schedule is still built by hand
The model is a coordinated digital representation of the facility. The schedule is a separate document assembled by a planner who reads drawings, decides what depends on what, and types activities into Primavera P6. The two artefacts describe the same plant, but nothing carries information between them.
- Manual sequencing takes weeks per facility and is repeated for every system.
- Two planners working from the same model produce two different schedules.
- Every model revision means the schedule is reworked by hand.
- Quantities and tags are re-keyed from the model into spreadsheets and then into P6.
The five stages, end to end
Each stage reads the output of the stage before it. Nothing is re-keyed. The pipeline was built and measured against real plant models rather than sample data.
| Stage | Input | Output |
|---|
| Extract geometry | Navisworks NWD model | Equipment hierarchy, object properties, geometry and metadata |
| Standardise data | Model properties, engineering spreadsheets, project cost and schedule data | One canonical equipment master and item-level inventory |
| Identify process areas | Inventory, model containment and connectivity, engineering documentation | Item-to-process-area assignment across the facility |
| Generate sequence | Process areas, equipment inventory, construction methodology | Dependency-correct activity sequence with area gating |
| Export to P6 | Scheduled activity network | Primavera P6 XER file with activities, relationships and resources |
Navisworks aggregates models from the discipline authoring tools, so the NWD already carries the object hierarchy and the engineering properties attached to each item. Sensali reads the equipment hierarchy, object properties, geometry and metadata directly, which removes the manual re-entry of tags and quantities that normally sits at the front of the planning effort.
Coverage spans structural steel, piping, electrical and instrumentation. Model properties are cross-validated against the project's own cost and schedule data so the inventory reconciles with what the project already believes it is building.
Process area detection
Sequencing only makes sense once every item belongs to a physical system. Sensali groups items into process areas such as inlet receival, acid gas removal and mercury removal, using model containment and connectivity data together with the project engineering documentation. Automatic process area detection has been measured at 98.8% accuracy on the models processed so far.
How the construction sequence is derived
Equipment is sequenced per physical unit through erection and grouting. Piping, electrical and instrumentation are sequenced per process area and gated on every piece of equipment in that area being ready first. Durations, crew sizing and resource logic come from the project engineering and staffing data rather than from estimates. This is construction methodology encoded as rules, not activities invented by a language model from a prompt. More detail on the rule set is on the construction sequencing automation page.
What lands in Primavera P6
The output is a Primavera P6 XER file containing activities, predecessor and successor relationships and resources, ready to import into P6. It is not a spreadsheet that a planner then has to rebuild inside the tool.
| Measure | Value | Note |
|---|
| Models processed | 4 | Full facility models run end to end through one combined pipeline |
| Activities generated | 220 | Construction activities produced from the models |
| Engineering hours | 264,101.9 | Calculated from the models |
| Relationships | 190 | Predecessor and successor links, P6 importable |
| Process area accuracy | 98.8% | Measured accuracy of automatic area detection |
| Crew sizing | 1:1 | Taken from project staffing data, not estimated |
How this differs from 4D simulation
Navisworks TimeLiner and comparable 4D tools attach an existing schedule to model geometry so the sequence can be visualised. They assume the schedule already exists. Sensali works in the other direction: it produces the schedule from the model. The two are complementary, and a generated schedule can be linked back into a 4D simulation once it is in P6.
Who this is for
EPC contractors and owner's engineering teams running planning and project controls on oil & gas, LNG and industrial gas plant construction, where the P6 schedule has to stay connected to the engineering model. Sensali is based in Perth, Western Australia and works with planning teams globally. Plant models and schedules are commercially sensitive, so an NDA is available before any project data is shared and no project data is reused between customers.