What Is 4D and 5D BIM?

4D and 5D BIM extend a 3D building model with time and cost. 4D BIM links model objects to the activities of a construction schedule so the build sequence can be played back and checked. 5D BIM attaches quantities and unit rates to the same objects, producing cost estimates that update when the design changes.

The labels sound like marketing, but the idea behind them is simple. A BIM model is a database of objects, and every object can carry more than geometry. Give a wall a start date and you are doing 4D. Give it an area, a rate and a cost code and you are doing 5D. The hard part is not the software; it is keeping the model, the programme and the estimate talking to each other as the project moves.

If you are still getting comfortable with the basics, start with our beginner's guide to the BIM industry. Below: what each dimension contains, how 4D and 5D BIM feed each other, which tools do which job, and why the numbers after 5D are disputed.

What Is 4D BIM?

4D BIM is a 3D model in which each object is linked to one or more tasks in a construction or phasing schedule, so the model can show what exists on site at any date. The U.S. General Services Administration puts it plainly in its BIM Guide Series 04: 4D Phasing (version 1.0, 2009): 4D modeling "combines a 3D model with time (via a schedule)", and 3D objects "are linked to specific activities" so they appear or disappear according to the programme.

What a 4D Model Actually Links

A 4D model has three ingredients. The first is the 3D model, usually split by zone, level or pour so that its pieces match how the building will be put together. The second is the schedule, normally a critical path method (CPM) programme built in Primavera P6, Microsoft Project or Asta Powerproject. The third is the set of links between them, where each schedule activity is tied to a group of model elements and given a behaviour such as construct, demolish or temporary.

Temporary items matter more than most beginners expect. The GSA guide notes that swing space and construction supports should appear only for their stated duration and then disappear. Cranes, scaffolding and laydown areas are what turn an animation into a planning tool, because they are usually what clashes in time and space.

What Teams Use 4D For

• Checking that the build sequence is physically possible, for example that a slab is not shown before the columns that carry it.
• Planning site logistics: crane reach, delivery routes, storage zones and access for each phase.
• Phasing occupied renovations, where tenants have to move out of one area while work continues next to them.
• Finding time-based clashes, such as two trades booked into the same room in the same week.
• Explaining the plan to clients, neighbours and inspectors who cannot read a Gantt chart.

The GSA guide is also honest about the limits. It states that 4D models "are neither intelligent nor automated" and "cannot modify or optimize the schedule automatically." A 4D model shows you a bad sequence; a planner still has to fix it.

What Is 5D BIM?

5D BIM adds cost to the model. Quantities such as lengths, areas, volumes and counts are extracted from model objects, matched to unit rates or cost codes, and rolled up into an estimate. Because the quantities come from the model, a design change can be re-measured in minutes rather than re-taken from drawings by hand.

Model-Based Quantity Takeoff

The first step is quantity takeoff. A well-built model already knows that a wall is 4.2 metres long, 3.0 metres high and made of a specific assembly. Revit and Archicad schedules can list those values directly, and dedicated takeoff tools read the model and group quantities by element type, material or classification code.

Takeoff is only as good as the modeling behind it. A slab modeled through a wall, or finishes drawn as one thick layer, gives wrong quantities that the software will not flag, which is why cost consultants audit a model before trusting it.

From Quantities to a Cost Plan

Quantities become cost when they are mapped to a measurement framework and priced. In the UK and much of the Commonwealth, that framework is the RICS New Rules of Measurement (NRM). RICS describes NRM 1 as covering order of cost estimating and cost planning for capital building works, and NRM 2 as the rules for detailed measurement of building works. In North America, estimates are more often organised by CSI MasterFormat divisions, the same structure covered in our guide to construction specifications and MasterFormat.

The point is consistency: an element tagged with the right classification code lands in the same cost plan line every time it is re-measured, so options can be compared on the same basis.

How 4D and 5D BIM Connect

Once the same model objects carry both a date and a cost, you can ask a new question: how much money is spent, and when? Linking the two produces a cost-loaded schedule. Every activity inherits the cost of the elements attached to it, and the project's spending curve (often called an S-curve) falls straight out of the programme.

That connection is useful in three practical ways:

• Cash flow forecasting. Owners and lenders can see monthly spending before work starts, not just the total.
• Change impact. When a design change moves a package by six weeks or adds material, both the date and the cost update together.
• Progress measurement. Comparing planned against installed quantities in the model gives an earned value picture that is tied to real objects rather than percentages typed into a spreadsheet.

3D vs 4D vs 5D BIM at a Glance

The table below summarises what each dimension adds and who usually owns it.

Aspect	3D BIM	4D BIM	5D BIM
What is added	Geometry and object properties	Time, via links to schedule activities	Quantities, rates and cost codes
Main question answered	What will be built?	In what order, and when?	How much will it cost?
Typical owner	Architects and engineers	Contractor's planner or BIM manager	Quantity surveyor or cost estimator
Key input	Design intent	CPM programme	Measurement rules and price data
Typical output	Drawings, coordinated model	Sequence simulation, logistics plans	Cost plan, cash flow curve
Main risk	Spatial clashes	Model and schedule drifting apart	Quantities from badly built objects

4D and 5D BIM Tools by Category

No single program does everything well, so most teams chain several together. Penn State's BIM Uses framework treats "Author 4D Model" and "Author Cost Estimate" as separate uses in the planning stage, and the tool market follows the same split.

Authoring Tools (the Source of Geometry and Quantities)

Revit and Archicad generate the objects that everything else depends on, and both can produce quantity schedules on their own. If you are learning Revit for this kind of work, ready-made families and templates from our Revit collection can save setup time, but the parameters for zone and cost code still need to be planned by you.

Scheduling Tools (the Source of Time)

Oracle Primavera P6, Microsoft Project and Asta Powerproject hold the CPM logic. They do not understand geometry, which is why their output is imported into a 4D tool rather than replaced by it.

4D Simulation Tools

Autodesk Navisworks Manage includes TimeLiner, which, according to Autodesk's TimeLiner documentation, imports tasks from Microsoft Project, Asta and Primavera and links them to model selections. Bentley presents SYNCHRO 4D as a 4D construction planning and scheduling tool for simulating sequences and testing what-if scenarios, and its feature list includes baselining the schedule for comparison against later updates. Kalloc Studios' Fuzor offers 4D construction sequence simulation alongside its visualisation tools.

5D Takeoff and Estimating Tools

RIB describes CostX as combining 2D and BIM takeoff with estimating in one platform. Autodesk Forma Takeoff (previously sold as Autodesk Takeoff) is, in Autodesk's words, a cloud-based quantification solution for 2D takeoffs and automated quantities from 3D models. Navisworks Manage also includes Quantification, which Autodesk's support documentation shows producing model takeoffs in a Quantification Workbook, and the same models feed clash detection in BIM, which is often the first coordination task before 4D and 5D work begins.

What About 6D and 7D BIM?

After 5D, the numbering stops being reliable. There is no single standard body that assigns meanings to 6D, 7D or anything higher, and different sources use the same number for different things.

The clearest evidence comes from a 2018 study in the Journal of Building Engineering by Rabia Charef, Hafiz Alaka and Stephen Emmitt, titled Beyond the Third Dimension of BIM. Their literature review found 52 papers on 4D, 15 on 5D, 6 on 6D and only 2 on 7D, and it identified "a confusion between academics and practitioners" for the 6D and 7D dimensions. In their survey of practitioners across the 28 EU countries, 86% of professionals using 6D assigned it to sustainability, and 85% of those using 7D assigned it to facility management.

So when a proposal or job ad mentions 6D or 7D BIM, ask what it means in that context. Some firms use 6D for energy and carbon analysis, others for operation and maintenance data, and a few add 8D for safety. The useful habit is to name the information you need (embodied carbon figures, asset registers, maintenance schedules) rather than the dimension number.

Where 4D and 5D BIM Fit in a Project

4D and 5D BIM are not one-off deliverables. They are most valuable when they start early and get updated at each stage:

1. Concept and schematic design: rough quantities from massing models support early cost plans and option comparisons.
2. Design development: element-level quantities tighten the estimate, and an outline 4D sequence tests phasing on complex sites.
3. Pre-construction: the contractor builds the detailed 4D model, plans logistics and loads cost into the programme.
4. Construction: progress is tracked against the 4D baseline, and changes are priced from the model as they come in.

Early cost feedback is also the basis of good value engineering, because alternatives can be priced while there is still time to adopt them.

Cost figures and outputs from 5D models are approximate and vary by region, price data, measurement rules and project scope. Always have estimates reviewed by a qualified cost professional.

To study the kind of fully developed model that 4D and 5D work builds on, our Autodesk Revit Pack for BIM Architects includes eighteen Revit models.

Where to Go From Here

4D BIM answers "when", 5D BIM answers "how much", and both depend on a model that was planned for those questions from the start. Names after 5D are still unsettled, so define the information you need rather than the label.

Your Next Step: Take a small model you already have, add a zone parameter to its elements, and link it to a ten-line schedule in a 4D tool. Then export the quantities for the same elements and price them with a simple rate table. Doing both on one small model teaches more about 4D and 5D BIM than any amount of reading.