Learn how to create a “Conceptual Mass” in Revit

To learn how to create a conceptual mass in Revit, start on the Massing & Site tab: click In-Place Mass on the Conceptual Mass panel to model a one-off form inside your project, or create a mass family from the Mass template and load it with Place Mass. You sketch a profile, use Create Form to turn it into a solid, click Finish Mass, then add Mass Floors to read areas and use the Model by Face tools to turn its faces into walls, roofs, floors and curtain systems. This guide is for students and early-career designers. It is a documented, sourced workflow based on Autodesk’s help pages, not a timed test.

Why conceptual masses matter

Many architects do not know at the start exactly what shape a project will take, and a first idea about a building’s form often changes radically before the final design. That has been true throughout the history of architecture, and early design tools need to allow for it.

Design practice is still moving from drawing projects in 2D CAD to modelling them with BIM, in which one model holds the geometry and data from which plans, sections and schedules are produced. This kind of software lets you test the overall volume of a building long before its walls and floors are designed, and the conceptual mass is the Revit tool built for that stage. For a wider look at the tools in this field, see our guide to architectural design software.

Most users know Revit as a documentation tool and know that its templates are specific to each discipline. Fewer use the tool for the very first outline of a building: the conceptual mass. A mass is an abstract volume, with no walls or floors of its own, that you can shape quickly to study proportion, height, setbacks and floor area. Because the mass can later host real building elements, the early study is not thrown away.

How do you create a conceptual mass in Revit?

Revit offers two routes, and choosing the right one first saves work later.

Route 1: an in-place mass inside the project

1. On the Massing & Site tab, go to the Conceptual Mass panel and click In-Place Mass.
2. Enter a name for the mass and click OK. Revit opens the conceptual design environment inside your project.
3. Draw a profile with the tools on the Draw panel (lines, rectangles, circles, arcs or splines), select it and click Create Form, choosing Solid Form (or Void Form to cut away from a solid).
4. Shape the form, then click Finish Mass.

These steps follow Autodesk’s help topic on creating an in-place mass. An in-place mass belongs to the project it was made in and cannot be reused in other projects.

Route 2: a mass family loaded with Place Mass

For a form you will reuse, or one you want to keep separate from the project file, start a new family from the mass family template (Mass.rft, or the metric equivalent in your template set), model the form in the same conceptual design environment, save it as an .rfa family and load it into the project. On the Conceptual Mass panel, Place Mass then inserts it, either from a family you have made or from a mass family supplied in a library.

Whichever route you use, the form you get from Create Form depends on what you select. Revit’s mass tools produce five types of form, summarised below.

Once a form exists, you edit it rather than redraw it. Select a face, edge or point and drag it with the arrows, add edges or profiles to give the form more control points, or change the levels and reference planes it is attached to. Step by step, the box becomes a tapering tower, a stepped block or a twisted volume. Masses are also useful to represent neighbouring buildings around a site, or as simple placeholder objects in an interior study.

The table below sums up when to use each of the two routes.

From mass to building: mass floors and Model by Face

A mass becomes much more useful when it starts to report numbers and host real elements.

• Mass floors. Add levels to the project, select the mass, and on the Modify | Mass tab click Mass Floors; tick each level that needs a floor and click OK. Each mass floor reports its area, perimeter, exterior surface area and volume, and you can build a mass floor schedule to assign uses or check the design, as Autodesk’s topic on creating mass floors explains.
• Model by Face. On the Massing & Site tab, the Model by Face panel offers Curtain System, Roof, Wall and Floor. Pick a face of the mass and Revit places the element on it. Use Floor by Face on mass floors, not on the outer faces of the form, and Wall or Roof by Face on the outer faces. A step-by-step version with screenshots is in this open tutorial on organic walls in Revit.
• Update to Face. If you change the mass after placing walls or roofs on it, select those elements and use Update to Face so they follow the new geometry.

If you prefer to design the form in another program, Revit can also import a design (for example a SAT or Rhino file) into an in-place mass or a mass family, as described in Autodesk’s help on importing a design as an in-place mass. Check the result carefully: a mass made only of mesh geometry cannot be used for mass floors, volume or surface area calculations.

Worked example: checking floor area with mass floors

Area checks like this are the main reason to learn how to create a conceptual mass in Revit early in a project. The arithmetic below shows the kind of check mass floors make quick. It is an illustrative example with round numbers, not a record of a modelled test.

• Site: 50 m x 50 m = 2,500 m². Assumed planning limit: a floor area ratio of 2.5, so up to 6,250 m² of gross floor area.
• Mass: an extrusion with a 40 m x 25 m footprint (1,000 m²), 21 m high.
• Levels: ground floor at 0 m and floors every 3.5 m up to 17.5 m, giving six levels inside the mass.
• Mass floors on those six levels: 6 x 1,000 m² = 6,000 m², a floor area ratio of 2.4, just under the assumed limit.
• Design change: set back the top two floors by 5 m on the long sides, so each is 40 m x 15 m = 600 m². The new total is 4 x 1,000 + 2 x 600 = 5,200 m², a floor area ratio of 2.08.

In Revit, the mass floor schedule updates as soon as you edit the mass, so you can try several volumes in minutes and keep the one that balances area against height and daylight. Always measure against the definition of gross floor area used in your jurisdiction; Revit’s mass floor area is a geometric figure and does not apply local rules about what counts.

Limitations and tips

• Plan the levels first: mass floors are created only where project levels cut the mass.
• Keep masses simple at the concept stage; very complex forms can make Wall and Roof by Face fail on some faces, and breaking the mass into simpler parts often helps.
• Use an in-place mass for a site-specific study and a mass family when the form will be reused or swapped between design options.
• Menu names in this guide follow Autodesk’s help for recent versions; check the help for the version you use.
• For the site around your mass, see our guide on how to create topographic surfaces in Revit.

Sources and next step

If you want to learn how to create a conceptual mass in Revit properly, build the worked example above yourself: one extrusion, six levels, mass floors, a schedule and one Wall by Face. It takes little time and covers every tool in this guide. The workflow here is drawn from Autodesk’s help pages and an open tutorial, linked in each section; it is a sourced guide, not a timed hands-on test.