Masses

Operation in Revit

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Masses

Objectives

Learn what are masses in Revit
Learn how to work with masses and create geometry
Learn how to create constructive elements from masses

Prerequisites

User will be using Revit, any version
User has basic skills in Revit Modelling
User has basic notions about geometry

Overview / Introduction

Masses are a particular category in Revit. It is independent from other categories from objects, and usually is a hidden category By default in views.

Although mass objects are three-dimensional, they do not have a constructive sense as other categories have. They are just geometry.

You can use massing objects to perform a variety of tasks, always in early phases of designs:

Create in-place or family-based mass instances.
Create mass families that represent the forms associated with often-used building volumes.
Vary materials, forms, and relations between masses that represent major components of a building or development.
Abstractly represent phases of a project.
Study zoning compliance, both visually and numerically, by relating a proposed building mass to the zoning envelope and floor area ratio.
Assemble various complex masses from a library of predefined mass families.
Generate floors, roofs, curtain systems, and walls from mass instances with control over element category, type, and parameter values. Fully control regeneration of these elements when the mass changes.
Model base structures that assist in the modelling of more complex structures (e.g. telecommunication towers, guyed masts).

Procedure

You can create masses within a project (in-place masses) or outside a project (loadable mass families).

In-place masses are used for mass forms that are unique to a project.

Go to Massing&Site Tab > In place Mass

Loadable mass families are typically used when you will be placing multiple instances of the mass in a project, or when you will use mass families in multiple projects. Also in case of a large reference mass containing subcomponents of other categories.

To create a Mass Family go to Revit main menu > Families > New… and in the Family templates folder, go to: Templates > English > Conceptual Mass > Metric Mass

Both ways use the same logic to create geometry, and are suitable to create:

Just plain geometry
Roofs, walls, curtain systems face based.
Insert external geometry in other formats.

To create in-place masses and loadable mass families, you will have to use the conceptual design environment.

Create geometry

The environment for creating masses is similar regardless of whether we create a family or an in situ mass. For this explanation, we use the creation of an in situ mass as an example:

Go to Massing&Site Tab > In place Mass, or Revit main menu > New Conceptual Mass

In the conceptual environment, we do not find the “Geometry Tools” buttons (such as Extrusion, Sweep, Blend, etc.) as we would in the family environment. However, the “Create form” tool uses the same logic as those specific tools.

For different data inputs we will get different results. Data inputs for geometry in conceptual environment are points, model lines and reference lines, placed in the correct workplane.

Data Inputs

For different data inputs:

Closed lines loop > We get a surface or an extrusion
Path and cross section profile > we get a sweep
Path and various cross section profiles > we get a sweep blend
Two parallel but different profiles > we get a blend
An axis and a profile > we get a revolve
We can get same solid and void forms and make boolean operations.

It is also important to control the order of drawing and selection when creating the geometry.

Model lines vs. Reference lines

What is the difference between choosing Model lines or Reference Lines?:

Model lines: They are actual lines or edges that will appear in the model when the family is loaded into the project.
Reference lines: They are reference elements that have no graphical visualisation when loading or creating the mass in the model, but are a good basis to create geometry. Besides they have four associated workplanes, two intersect in the longitudinal dimension and define the line. Other two are perpendicular to the line at its ends.
Choose in each case the line that best fits to the purposes of the component.

Actual geometry

Create then the needed elements: points and lines of reference lines that will be the data input for every piece of geometry that we want to model. And use “Create Form”:

Remember that geometry can be solid or void. Combinations of solid and void geometry are used to perform boolean operations.
Remember also that when creating a Mass there can be created several pieces of geometry inside the same Mass object. This is especially relevant when we want to perform boolean operations with voids.

In addition to solid geometries, we can create wireframe structures that serve as a basis for further modelling in the project. For this we will use:

Reference points. These points have their corresponding 3 reference planes, which allow us to use them to model with respect to the point planes.
Model lines using the Spline Through Points tool: These lines will be connected to the reference points, and in case the distance between the points changes, the line will move with them.

Divided Path: Starting from a model line (or reference line) we use the Divided Path tool to divide this line into equal parts. This element can then be parameterised to control the number of divisions from the project.

Divided Paths have the following characteristics:

As we modify the distance between the origin points, this Divided Path will adapt.
We can intersect our Divided Path with different reference planes, so that we can control the division in a different way according to our interests, for example, using a parameterised measurement.

Repeater: Once the Divided Path is created, it is used to create repeaters along its points. For this, we will have to insert an adaptive family with at least 1 adaptive point, to place it in one of the points of the Divided Path. We can use the Divided Path intersected with the reference planes, or directly the one that divides in equal parts.

This repeater can be created using 1 single Divided Path or multiple. For example using an adaptive family based on 4 points:

Divide Surface. It works similarly to Divided Path, but in two directions. We can use its points to place again adaptive families that go all over the surface using the Repeater tool. For example, using a three-point adaptive surface:

To display the division nodes: Modify|Divided Surface / Surface Representation:

Use of lines as a reference. Sometimes, we need to place a point that is "new" through a line, or we want to place it in function of the line. For example, a point placed on a surface to make an equilateral triangle (this would be quite complex to do with constraints).

In the case of the Measurement Type, we have several options:

Non-Normalized Curve Parameter: Identifies the location of the reference point along a circle or ellipse. Also known as raw, natural, internal or T parameter.
Normalized Curve Parameter: Identifies the location of the reference point on the line as a ratio of the length of the line over the total length of the line. Its value can vary from 0 to 1.
Segment Length: Identifies the location of the reference point on a line by the length of the line segment between the reference point and the end point of measurement. The segment length is represented in project units.
Normalized Segment Length: Identifies the location of the reference point on the line as a ratio of the Segment Length over the total length of the curve (0 to 1). For example, if the total length of the curve is 170', and the point is located 17' from one end of the curve, the value of the % curve length will be 0.1 or 0.9 depending on which end is being measured.
Chord Length: Identifies the position of the reference point on the curve by the straight line distance (chord) between the reference point and the measured end point. The chord length is represented in project units.
Angle: Available for points on arcs and circles. Identifies the location of the reference point along an arc or circle represented as an angle.

Mass families

For the creation of mass families, the procedure for modelling the geometry is the same as described above, since the modelling environment is the same if we use in-situ mass modelling as if we use the family environment.

When creating a mass family, you can do the following:

Define any restrictions and parameters needed to control the geometry.
Nest other mass families into the mass family that you are creating.
Import geometry from other applications into a mass family.

Masses in project

In a project, you can do the following:

Create an in-place mass.
Place one or more instances of a mass family.
Join a mass instance to other mass instances to eliminate overlap. As a result, their gross volume and gross floor area values adjust accordingly.
Import geometry from other applications into an In-place Mass.
Create Roofs, walls, curtain systems face based, both from Mass families and In-place masses.
Create a schedule that shows the gross volume, gross floor area, and gross surface area of a mass (both family and in-place).
Place mass instances in worksets, assign them to phases, and add them to design options.

We will describe some of the operations that can be performed with the masses in the project environment.

Model by face

From the different faces of a mass geometry, we can create constructive elements like roofs, walls, curtain systems and floors. They will perform as regular roofs, walls, curtain walls and floors in their composition, but the form they take will be always linked to the face they come from

Floor modelling by face

First, create the mass floors. They are the intersection between the mass and the project levels:

Select the mass > Mass Floors

Then you can already use the Floor by face tool:

Massing&Site tab > Floor by fac

Curtain System / Roof / Wall modelling by face

First, we create the mass floors. They are the intersection between the mass and the levels of the project, so first we have to create the levels:

Massing&Site tab > Curtain System / Roof / Wall

We select the tool, and then we pick the face we want to convert into one of these three kinds of elements.

Notice that:

We will be able to convert a whole face, not a portion of it.
For sensibly vertical faces you could be able to create walls / curtain systems.
For sensibly horizontal faces you could be able to create roofs / curtain walls.
If the mass changes the elements can be updated to meet again the form of the face.

Update to face

When we have created elements by face and the base mass changes, those elements will not automatically update their form. This action has to be performed consciously.

Select the element > Update to Face.

Keep in mind that this option will not be valid if the geometry in mass is completely removed and rebuild. It will only work if the geometry is just edited, but not deleted.

It is impossible to re-associate an element-by-face to a face different from the one from which the object initially (roof/wall/curtain system) was created.

Summary

Masses are a powerful tool in early stages of projects. They allow the designer to check the initial proposals in terms of area, volume, and associated costs.

They are also very useful to create complex geometry where basic revit elements (floors, curtain walls, walls,...) are not suitable tools for the desired results.

Tips & Tricks

By default Masses are hidden in views.
Mass geometry is associated to workplanes, both in mass families and in-places masses (levels and reference planes in project).
You can also add parameters in in-place masses as you would in mass families.
Remember that when you copy an in-place mass it will become a totally different object with no association to the original. Try to use them sparingly.