01
Why Revit does not hand you a plaster quantity
Plaster belongs to the room, but Revit files a finish under the wall. A wall has two faces. They can sit in two different rooms, carry two different specifications and stop being plastered halfway up. On top of that, some plastered surfaces are not walls at all: beam sides, beam undersides, column faces and ceilings.
Every native route therefore either flattens the difference between the two faces or stops at the wall, and the surfaces that are not walls are measured by nobody. That is why the same model produces different plaster numbers depending on who took it off.
02
The methods, side by side
| Method | What it gives you | Where it breaks |
|---|---|---|
| Room finish schedule | The name of the finish for each room. | It never returns a measured area. Perimeter × height stops being the plaster area once there is an opening, a reveal, or a wall only partly inside the room. |
| Paint / Material Takeoff | Area per material, with the faces you selected. | Faces are selected by hand and selected again after a layout change or a wall type swap. Reports one net area, so it cannot apply an opening threshold. |
| Plaster layer in the wall type | A project total, with no per-wall effort. | Cannot say which room the plaster is in, cannot measure surfaces that are not walls, and adding the layer to a model built to the wall core moves every wall face. |
| Dynamo or an in-house script | A number per room, once the graph is written. | Works until it meets a beam that splits a room in two, or a curved wall. Then it returns a confident number instead of an error. |
| Areas exported and deducted in a spreadsheet | The fastest route and a good rough check. | It becomes a second model of the building that nobody maintains as carefully as the first, and it assumes perimeter × height. |
| Plaster modeled as real elements | A schedule row per plaster element, with room, net area, reveals and total. | Needs a tool that builds the geometry. Geometry the tool cannot handle must be reported, not approximated. |
No method is wrong for every job. A layer in the wall type is the right answer for a quick project total; a spreadsheet is a fine sanity check.
03
A worked example: one room, two rules, two numbers
Take a room of 4.00 m × 5.00 m with a 2.80 m ceiling, 20 cm walls, one door (0.90 × 2.10 m) and one window (1.20 × 1.40 m). The figures below are an illustration to show the mechanism, not a project result.
| Step | Working | m² |
|---|---|---|
| Gross wall face | perimeter 18.00 m × 2.80 m | 50.40 |
| Door and window openings | 1.89 + 1.68 | 3.57 |
| Reveals (20 cm deep) | door 5.10 m + window 5.20 m of edge × 0.20 m | 2.06 |
| Rule A: every opening deducted | 50.40 − 3.57 + 2.06 | 48.89 |
| Rule B: openings under a threshold measured through | 50.40 + 2.06 | 52.46 |
Same geometry, a 3.57 m² difference (about 7%) that comes entirely from the contract clause. A schedule that hands you one net figure cannot show you that difference, because the openings were already gone when it added up. See how measurement rules differ between Türkiye, the UK and Germany.
04
Doing it as geometry: what SivaTools changes
SivaTools reads the room boundaries and builds the plaster as real Revit geometry on the faces that are actually plastered, joined to the structure, cut by the openings and attributed to the room. The takeoff is then an ordinary Revit schedule, because the thing being measured exists in the model. Your wall types are left alone.
- Wall faces, one room and one side at a time, so two finishes on one wall stay two quantities.
- Beam sides, beam undersides, column faces and room ceilings.
- Reveals kept as their own quantity instead of being deducted with the opening.
- Exterior faces of external walls.
- Curved walls are not approximated: they are skipped and listed in the report.
On the two-storey demo project the run produced 218 plaster elements, 1,278.95 m² of net area and 35.96 m² of reveals, for a plaster area of 1,314.92 m². A layer-based takeoff reports those reveals as zero. Every row of the schedule traces back to an element you can select in the model.
05
Questions people ask
Can Revit calculate plaster area automatically?
Not from a single built-in command. A room finish schedule names the finish and a Material Takeoff reports an area for a material, but neither gives a measured plaster quantity per room and per wall face with openings and reveals handled.
Does a Revit Material Takeoff subtract openings?
It reports one net area with the openings already subtracted. That is correct under a deduct-every-opening rule, but it cannot apply a threshold rule.
Should reveals be part of a plaster quantity?
That depends on the measurement rule in your contract. Reveals are real plastered surface, so report them as their own line rather than losing them inside the opening deduction.
Which Revit versions does SivaTools support?
Autodesk Revit 2024, 2025, 2026 and 2027 on Windows, with separate builds for each.
Does SivaTools upload my Revit model?
No. Model names, file paths, rooms and quantity data stay on your computer. The internet connection is used only for license validation. Read the privacy notice.