Exploring Spaces in ACA

Spaces are two-dimensional or three-dimensional style-based architectural objects that contain spatial information about a building, including floor area, wall area, volume, and surface information. Spaces have a multitude of uses, spanning the conceptual design through construction documents phases of a project. Among other things, spaces can begin to define the layout of a building’s internal rooms and areas. They can also define rooms and areas for scheduling purposes and for area calculations and evaluations.

Overview of Space Types

Both associative and non-associative spaces can be modeled in AutoCAD® Architecture. Associative spaces are generated from boundary objects. When the boundary objects change, the space updates accordingly. In addition to associative spaces you can also create non-associative spaces with user-defined geometry. A non-associative space can stand alone in the drawing, but you can use it to generate calculations just as you would with an associative space. Non-associative spaces can be connected to boundary objects after their creation; similarly, associative spaces can be disconnected from their boundary objects.

2D spaces display spatial information in two plan dimensions. The Z direction is by default set to 0 and ignored during creating, editing, and scheduling the space. 2D spaces can be rectangular or polygonal and they can either be non-associative or associative. A 2D space can be bounded by 3D objects and linework. 2D spaces are typically used for plan views, where 3D information is not needed.

An extruded 3D space is similar to a 2D space, but has a user-defined extrusion height. Extruded spaces are useful for regularly shaped 3D spaces such as uniform-height rooms in a building. Extruded spaces can have floor and ceiling components and space above the ceiling and below the floor. The space above the ceiling is often used to place ductwork, cables, and electrical installations in a room. Extruded 3D spaces can be associative to 3D objects and linework, but they are bounded only in the X and Y directions. The Z direction is defined by the extrusion height.

If you need a space that is fully bounded by objects in all three spatial dimensions, you need to generate a 3D freeform space. 3D freeform spaces are generated from boundary objects such as walls and slabs, and are associative to them. Associative 3D freeform spaces must be bounded in all directions to form a valid boundary shape. A 3D freeform space is a complex 3D geometry with any number of surfaces needed to generate the space shape.

Space Styles

A space style is a set of parameters that determines the appearance and other characteristics of the space object to which it is assigned. Depending on the scope of the drawing, you may want to create different space styles to represent different types of spaces, such as different room types in an office building.

You can use styles for controlling the following aspects of spaces:

  • Boundary offsets – You can specify the distance that a space's net, usable, and gross boundaries will be offset from its base boundary. Each boundary has its own display components that you can set according to your needs.
  • Name lists – You can select a list of allowed names for spaces of a particular style. This helps you to maintain consistent naming schemes across a building project.
  • Target dimensions – You can define a target area, length, and width for spaces inserted with a specific style. This is helpful when you have upper and lower space limits for a type of room you want to insert.
  • Displaying different space types – You can draw construction spaces, demolition spaces, and traffic spaces with different display properties. For example, you might draw all construction areas in green and hatched, and the traffic areas in blue with a solid fill.
  • Displaying different decomposition methods – You can specify how spaces are decomposed (trapezoid or triangular). If you are not working with space decomposition extensively, you will probably set it up in the drawing default.

Spaces can have a “Name” property assigned. These are derived from a List Definition. The List Definition should be assigned to the style so you have a valid list of names to select from when establishing the space object’s properties. Space style names should be indicative of the type of room or area the space style is meant to address. Space styles should have materials assigned to their “Floor” and “Ceiling” components.

To create a space style, begin by clicking the Manage tab on the ribbon, select the Style & Display panel, and then select Style Manager (see Figure 1). The Style Manager will display with the current drawing expanded in the tree view. Expand Architectural Objects and then expand Space Styles. You can create a new space style by right-clicking on Space Styles and selecting New (see Figure 2).

You can also create a space style from an existing style by right-clicking the space style you want to copy and select Copy. Next you will right-click and select Paste. Enter a name for the new space style and hit Enter. Now you will need to edit the new space style according to how the space should appear—its size, and so on. Once finished, you can add the new space style to your tool palette for easy access.

Figure 1: Ribbon

Figure 2: Style Manager

Space Evaluation

The space evaluation is a documentation feature that calculates and evaluates the space information of your finished floor plan. This information is stored in a separate file that you can export to a spreadsheet or word processing application. Evaluation templates ensure that the information is formatted and arranged in a consistent, structured way.

Architects need the space evaluation feature for submitting floor plans to the building plan approval authorities and to customers. Space evaluation can also be used for performing cost estimates, assigning jobs to contractors, or organizing facility management. Evaluations can be created for selected spaces in the current drawing, selected spaces from multiple open drawings, all spaces in a drawing, and all spaces from all open drawings. Spaces can also be evaluated from external references.

Areas are converted to spaces, area groups to zones, and the area evaluation has been converted to the space evaluation. If you attempt to use a legacy tool or run a legacy command to start the area evaluation, the following message will appear: “The command AreaEvaluation is no longer supported” (see Figure 3). If you click Run Space Evaluation, the space evaluation will be started instead. You should remove area evaluation tools from your palettes and exchange area evaluation commands for space evaluation commands in your scripts.

Figure 3: Space evaluation

Space Boundaries

Spaces have four different boundaries: base, net, usable, and gross. You can use them to display, edit, and schedule different aspects of the space. You can choose that these boundaries are not offset from each other and lie on top of each other. If you do not need different boundaries, you can even turn off the display components for the additional boundaries. Here are some typical use cases for using individual boundaries:

  • Base boundary – Normally representing the inner area of a room covered by a space. This is the area generated by boundary objects in an associative space. In most cases, the base boundary is identical to the net boundary, except in some area calculation standards like the Swedish SIS standard.
  • Net boundary – This boundary can be used for planning and detailed design. For example, if you need to determine the hiring of cleaning personnel for an office, you would use the net area as the calculation basis. The net boundary can also be used for special applications when the calculated area of a space is smaller than the base boundary.
  • Usable boundary – This boundary is in many area calculation standards used for planning and detailed design, renting calculations, tax and other duty calculations, statistical calculations, maintenance, pricing, and more. The usable boundaries typically extend from the inside of the exterior walls to the middle of the interior walls (or a specified distance into the interior walls).
  • Gross boundary – The gross boundary can be used in connection with cost calculation, price estimation, calculation of tax and other duties, key numbers for the building or a specific floor, and more. Normally, the gross boundary is measured from the outside of the exterior walls to the middle of the interior walls.

There are different ways to determine how the boundaries should be offset from each other and calculated. These are Manual, By Style, and By Area Calculation Standard. It is important to note that in previous versions of the software, objects that were invisible due to a frozen or hidden layer were never included in the generation or update of associative spaces. Beginning with this version, frozen and hidden objects are included in the space generation and update if they are set as boundary objects.

Creating Spaces In Your Drawing

AutoCAD Architecture provides tools that allow you to quickly place spaces by selecting a space tool with a specific space style as well as other predefined properties. You can use the tool as is with its default settings or you can change any of the properties that are not controlled by the style.

You can also use space tools to apply tool properties to existing objects to create new spaces. Space tools can be found on the Space tab of the tool palette. To begin creating spaces in your drawing, drag and drop the desired space from the tool palette to your drawing and begin. You can also find space tools in the Stock Tool Catalog, the Sample Palette Catalog, and the Design Tool Catalog. Once you are in the Space command, the Space tab will appear in the ribbon (see Figure 4).

You can also create spaces in your drawing by converting polylines, object outlines, and profiles to spaces. Simply open the Space tool palette and right-click on the space tool you wish to use. Next, select Apply Tool Properties To and then select Linework And AEC Objects (see Figure 5). Select the objects and/or polylines you wish to convert and hit Enter. Under Cut Plane Height on the Convert to Space worksheet, enter the height at which the object should be cut to generate the profile of the new space. Select OK.

Another way to generate an associative space in your drawing is to begin by verifying that all necessary boundary objects have their Bound Spaces property set to Yes. Open the tool palette that contains the Space tool you want to use and select it. For Offset boundaries, select how the four space boundaries (base, net, usable, and gross boundary) are calculated:

  • Manual – The net, usable, and gross boundaries can be manually edited with grips.
  • By style – The net, usable, and gross boundaries are offset from the base boundary by a value defined in the space style.
  • By standard <Standard Name> – The net, usable and gross boundaries are defined by the area calculation standard listed.

On the Properties palette, for Create type select Generate. It is important to note that the Associative property is interlinked with the Create type. If the Create type is Generate, the Associative setting defaults to Yes. If the Create type is Insert, Rectangle, or Polygon, the Associative setting defaults to No and becomes read-only. Select Yes for Allow Overlapping Spaces if you want to be able to generate spaces from boundaries that already contain a space. This could be useful if you want to generate spaces from an xref drawing that already contains spaces, but you need to generate spaces with different settings. For Geometry type, select 2D, Extrusion, or Freeform. In the drawing, generate the spaces. If you want to generate a 3D freeform space, enter “G” (generate all). If you want to generate a 2D or extruded 3D space, you can either enter “G” (generate all) to generate spaces for all visible boundaries or you can pick inside closed boundaries in order to generate spaces for them.

Figure 4: Space tab

Figure 5: Apply tool properties


Spaces are an essential part of AutoCAD Architecture software. They help you extract data contained in the drawing for use in scheduling, tagging and analysis. Spaces are an integral part of enhancing your productivity for facility management as well as the working drawing phase of your project. I encourage you to explore the possibilities with spaces and see how far you can go!

Appears in these Categories