1. Home
  2. Requirements definition
  3. Making a decomposition of spaces

Making a decomposition of spaces

Spaces are created and defined in the ‘tree’ called Building / Spaces. This tree (which you can also refer to as a ‘breakdown’ or ‘decomposition’) is usually the most important part of the project. This is because spaces typically carry most of the project’s requirements (on indoor climate, elements that need to placed etc.). Basically, you are making a room book (also referred to as room data sheets) for a project.

Don’t forget to check out our video on this topic!

Different types of objects

When creating this tree, you will be able to use different types of objects to help structure your tree:


This object is defined as a general geographical area or zone (e.g. a city district or university campus) that can contain multiple specific locations. The object can be used to capture, for example, zoning requirements.


This object represents the specific site, address or plot where a built asset is located or must be realised.

Please note that area () and location () are mostly relevant for urban development or infrastructure projects. When defining the requirements for a building’s renovation or a fit-out project, you will probably not need them.


This object can be used as a starting point for a breakdown of all the spaces that should be located in the same building.

Please note that it is necessary to include this object in your spatial decomposition if you want to be able to calculate the overall gross floor area of a project as the GFA/UFA factor is a standard property of the building object.

Group of Spaces

This object can be used to indicate larger areas or parts of a building which can then be broken down or subdivided into individual spaces. Examples of grouping areas include departments in hospitals, the entrance area of a public building or a conference center at a campus.  


This object is the most basic unit of the project’s space tree. They are the actual volumes where user activities take place. Spaces are the most important objects of the model as they carry most of the requirements. They can have a size, capacity, particular room items, acoustic qualities, and so on.  

Important: spaces are the lowest level of the tree: they cannot be further subdivided into smaller units. This is to avoid create confusion about to which (sub)spaces requirements apply. Furthermore, it allows for the integration with BIM models.  

Outdoor Spaces

This object is essentially the same as the regular spaces above, but specifically labelled as being outdoors. Examples of outdoor spaces are parking spaces, playgrounds, and bicycle storage. Linear elements, such as foot paths or roads can also be considered outdoor spaces.

Please note: it is important to distinguish between outdoor spaces and indoor spaces in your model to make sure that the sizes of your outdoor spaces are not calculated in the total floor area of your project.

Creating objects

Go to the Building / Spaces tree and click on the at the top of the page. This will allow you to create your first spatial object. A window will pop up offering you four options to choose from (as discussed above). Once you click on one of the options and a name for the object.

When hoovering over the , you will get a short explanation about the object type

When creating and organizing the spaces for your project, it is good to know that you can easily move objects around, search for objects, rename them, delete them if necessary, and you can easily clone (copy/paste) them if you want to use the same type of space elsewhere in your break-down.

This can all be done by using the presented buttons in your screen. For a general explanation about these buttons, click here.


Typically, a spatial break-down is structured as follows:

  • You often start with a building object as the top object of your tree (assuming your project concerns a building).
  • Next, there are likely to be one or two levels groups of spaces which can be used to cluster spaces of a particular kind (e.g. meeting spaces), or for a particular user (e.g. department A or B).
  • And, ultimately, at the lowest level there will be spaces with all the specific requirements.
  • Outdoor spaces are often located on the same level as the building, unless it concerns outdoor spaces that are part of the building (e.g. roof terrace).

Making such a break-down is also referred to as a processes of decomposition, in which you start with a top object (e.g. building), which is step-by-step, divides up until smaller parts. These parts become more concrete, more detailed and more ‘material’ as you work you way down the decomposition structure.

See for a simple example below.

Small example of a spatial break-down: the building has a conference area, and the conference area consists of a various kinds of meeting rooms, a coffee corner and a cloak room.

Please note that you do not have to make a full decomposition of your project straight-away. In the early project phases, it is often sufficient to indicate some large ‘chunks’ or groups of spaces, which can become more detailed as the project progresses. Trees can grow, so to say : – )

Was this article helpful?

Need Support?
Can't find the answer you're looking for? Don't worry we're here to help!

Leave a Comment