Services · 04
Revit BIM Modelling
Outsource Revit modelling to an engineer: CAD to BIM conversion, architectural and structural models, BIM quantity take-off and as-built models.
Who it is for
- Architecture practices in the UK, Europe and the Gulf that outsource modelling
- Contractors on projects with a BIM requirement but no in-house Revit team
- Contractors who want quantities straight from the model (5D)
- Owners and operators who need an as-built model
What it fixes
- The employer's requirements call for BIM, but nobody in the team uses Revit at project scale.
- You only have 2D DWG drawings, so quantities are re-measured on every revision.
- A model exists, but it was not set up for take-off and its schedules do not match the BOQ.
- The building is finished and facilities management wants a model that matches what was built.
Scope and deliverables
| Item | Deliverable |
|---|---|
| 04.01 | Architectural and structural Revit model (level of detail agreed with you) |
| 04.02 | CAD to BIM conversion from DWG drawings |
| 04.03 | Quantity schedules from the model, mapped to BOQ items |
| 04.04 | As-built model with site changes incorporated |
| 04.05 | Project-specific Revit families |
| 04.06 | Drawing sets (PDF and DWG) |
How I work
- Step 01
Scope and detail
We agree what the model is for. Take-off, coordination and as-built each need a different level of detail, and that drives cost.
- Step 02
Template and setup
I set up the project template, levels, grids and the parameters needed for take-off. BOQ codes live in the model as parameters.
- Step 03
Modelling
I build the model discipline by discipline and share interim issues. Conflicts in the design drawings go into a separate list.
- Step 04
Take-off and handover
I export quantity schedules in your BOQ format and hand over the model and schedules together.
An engineer’s model
There are many Revit modelling providers, and plenty of them are cheap. My difference is that I build the model as the source of quantity and cost data, not only as a set of drawings. After years of measurement and payment work in technical offices, I know which information needs to sit in the model as parameters and which items will never come out of it.
That approach is usually called 5D BIM: linking model quantities to cost and programme. Even if your project does not need a full 5D process, taking quantities reliably from the model saves days on every revision.
How model-based take-off speeds up payments
Take-off from 2D drawings means re-measuring every affected item on each revision. When the model is set up for take-off, the revision goes into the model and the schedules update. At valuation time the job becomes checking rather than measuring. Because BOQ codes live in the model, schedules export directly into the payment application format.
There are limits. Scaffolding, temporary works and over-excavation do not appear in a model. I prepare those as a separate list and combine them with the model quantities.
Example scenario
A practice in the UK is producing construction drawings for a residential scheme and the client asks for a Revit model. The practice has one Revit user who cannot cover a project of this size. I build the architectural and structural model from the practice’s DWGs, produce sheets in their title block and standards, report inconsistencies between drawings in a separate list, and export the quantity schedules the client has asked for.
Level of detail and cost
What drives the price of a model most is the level of detail. At concept stage walls and floors are generic types. For construction and take-off you need build-ups, finishes and structural detail. Modelling everything at the highest level inflates both time and budget. Before starting we agree what decisions the model has to support and fix a level of detail per element. That table also becomes the checklist for handover.
As-built models
When a building is finished, the most useful document for the operator is a model that shows what was actually built. I incorporate site changes, revision registers and as-built drawings into the model and hand over something facilities management can use.
Questions clients ask
Which Revit version do you deliver in?
The one you use. Revit files do not open in older versions, so we confirm this before work starts.
What makes you different from lower-cost modelling providers?
I am a civil engineer who has spent years on measurement and payments. The model is set up so the quantities can be used for costing, not just for drawings, and I flag design conflicts an engineer would notice.
Can quantities from the model go straight into a BOQ?
If the model is set up for it, yes. Items the model cannot show, such as temporary works or scaffolding, are listed separately and added to the model quantities.
We only have PDF drawings. Can you still model?
Yes, but it takes longer than working from dimensioned DWGs and needs dimension checks. I state the difference in the proposal.
Do you model MEP?
My focus is architectural and structural models with take-off. Where MEP is needed we agree the scope clearly and usually keep it to coordination level.
Who owns the model?
You do. Ownership of the delivered model and families is written into the service agreement.
New project
Tell me about your project in a few lines.
Describe what needs doing and we will pin down scope and timing together.