Design SuiteSlab preferences

Slabs include the ability to define components, set slab attributes and drainage settings, and more. Slab preferences are set from the Slab Preferences dialog box when drawing a slab. The parameters can be edited later from the Object Info palette.

Click to show/hide the parameters.Click to show/hide the parameters.



Slab Style

From the Resource Selector, double-click a slab style to select it. Because slabs can be used to create flat roofs, roof style resources are also available.

If a selected slab style's parameters are edited in the Slab Preferences dialog box, the slab style automatically changes to unstyled, indicating that the edited style must be saved as a new style to save changes (alternatively, the changes can be applied as an unstyled slab, and they are not saved).

Convert to Unstyled

Converts a styled slab to unstyled

Save Preferences as Slab Style

Saves the current preference settings as a new slab style. The Assign Name dialog box opens; enter a slab style name (see Creating slab styles).




Displays a sectioned preview of the slab structure, including any defined components. The top of the preview indicates the top part of the slab as it will be drawn.

Overall Thickness

Displays the thickness of the slab. The slab thickness is always determined by the thickness of its components; a slab always has one component by default.

Edit Slab Attributes

Opens the Slab Attributes dialog box, to specify the slab fill and pen settings; see Editing slab attributes


Select whether the datum is applied to the top or bottom of the designated component; the indicator in the Datum column updates accordingly. A datum is the reference point for elevation settings; for slabs, it is fixed vertically (it does not change with any changes to the slab thickness or definition). One of the slab components is designated as the datum component.


Select whether the slab is of fixed thickness or has a tapered component to assist with drainage. Click in the Tapered column to designate the tapered component.


Lists the components that form the structure of the slab, in order from top to bottom as displayed in the preview. To change the order of a component, click and drag within the # column.

If multiple components are selected, changing the order moves all selected components to the new location.


Click in the column to designate the datum component. An indicator in the column points towards the top or bottom, to show that the datum is placed on the top or the bottom of the component. To change the datum to be at the top or bottom, either click on the indicator to switch the placement, or click Top of component or Bottom of component in the Datum section of the dialog box.

The reference datum of the slab can be set to the active layer elevation value, or set to be bound by one of the story levels defined for the story or the story below it (Architect or Landmark required). By setting the slab datum to a level type, if the elevation of the associated story changes, the datum of the slab changes automatically to match.


If Tapered component is selected in the Drainage section of the dialog box, click in the column to designate which component is tapered. The bottom surface of the designated component is flat, and the top surface is tapered to incorporate the drainage. All components above and below the tapered component are of uniform thickness to maintain the taper that the designated component brings to the overall slab.

Other Component settings

The remaining columns in the component list display the current settings for the slab, from the Slab Component Settings dialog box.

If the slab is a hardscape slab, some architectural parameters do not apply.


Opens the Slab Component Settings dialog box to define the components of the slab; see Creating slab components for information on creating components


Opens the Slab Component Settings dialog box to edit the attributes of one or more selected components; changes are made to all selected components. Alternatively, to edit a single component, double-click the component to open the Slab Component Settings dialog box.


Duplicates one or more selected slab components; the duplicates are added to the component list right below the originally selected components


Deletes one or more selected slab components; the slab thickness is adjusted accordingly

Insertion Options




Datum LayerZRef

Sets the slab’s datum height to be defined by the layer elevation, or set it to be bound by one of the story levels defined for the story or the story below it (Architect or Landmark required). By setting the slab datum to a level type, if the elevation of the associated story changes, the datum of the slab changes automatically to match.

Datum Offset from Layer Z

Specifies the offset (positive or negative) of the slab’s datum component from the layer elevation (see Setting design layer properties)


Specifies the default class for the slab

Drainage Settings

Click to open the Slab drainage settings dialog box


(Architect required)

Slabs can participate in Energos energy analysis calculations (see Energos energy analysis module). Vectorworks Architect is required to conduct an energy analysis; however, energy-related parameters can be specified here for informational purposes.

Include in calculations

When selected, the slab is eligible to be included in energy calculations, depending on the energy analysis settings for layer/class, element inclusion, and so on

Energy Function

Select whether the slab is a floor slab or roof slab

Object Boundary Type

Only certain slabs participate in energy analysis calculations; select the type of slab.

The system list can be modified; see Specifying system sets. Editing the system parameters, or adding new ones, allows the exterior and interior RS (surface resistance) values to be specified. If the selected boundary slab calculations are not satisfactory, edit the system list to be extremely specific about the slab surface resistance parameters.


For a finer level of detail about special boundary slabs, click Advanced. The Advanced Settings dialog box opens. If the slab is a special type of slab that should participate in energy calculations, select Special type and then select the Type from the list and specify its parameters.

Heated Basement or Underground Floor Slab: Specify the basement depth, and enter the R-Value/U-Value for the virtual walls that surround the slab below ground level.

Unheated Basement: Specify the basement depth and height of the walls above ground, and then enter the R-Value/U-Value for the virtual walls that surround the slab below ground level, and above ground level. Indicate the air change flow rate and the volume of the unheated space.

Suspended Floor: For crawl space slabs, enter the height and R-Value/U-Value of the crawl space walls (the walls around the suspended slab). Specify ventilation parameters for the crawl space, entering the size of ventilation openings, the wind velocity, and wind shield factor (low factor for urban areas, with values around 0.1 for rural areas exposed to wind).

Slab on Grade: For slabs at grade level, enter the perimeter insulation width and thickness, and indicate the properties of any conductivity insulation. If horizontal insulation is present, select the option.

Calculated R-Value/U-Value

Based on the location of the slab within the building (boundary type) and orientation of the heat flow (surface resistance values), the slab R-Value/U-Value is calculated and displayed. This value, along with the size of the slab, is critical for a correct assessment of the building envelope in energy calculations.

Override calculated R-Value/U-Value

Select this option to override the calculated R-Value/U-Value and enter a manual value for the slab instead in Manual R-Value or Manual U-Value 


The Object Info palette Render tab has additional texturing controls for existing objects; see Managing object textures from the Object Info palette and Textures on objects with components. Textures applied from the Object Info palette override the textures set here unless the texture is set by style.

Use component textures

Uses the textures defined for the slab components to texture the slab.

This option can also be selected for an existing slab from the Render tab of the Object Info palette.

Use object textures

Uses the textures defined below for the slab parts 


Applies the texture selected in Texture to the selected parts of the slab

Revert to Overall

If a part was assigned a texture but it should inherit its texture from Overall instead, select the part and click Revert to Overall. The part moves back below the divider in the Part list, and (from Overall) displays as its texture name.


Applies the selected texture to the selected Part. If Class Texture is chosen, uses the texture defined by the slab’s class; see Concept: Applying textures by class. Any slabs with that slab style use the texture defined by the slab’s class for that part of the slab (unless overridden). If Texture is chosen, from the Resource Selector, double-click a texture to apply it to the selected Part. The texture set here overrides the object class texture.


Specify slab information. This information can be included in a slab style schedule. These parameters are optional; enter text only where desired.

If these slab preferences should be saved as a slab style, click Save Preferences as Slab Style. See Creating slab styles.

A saved or selected slab style is saved as a resource in the file, and displays in the Resource Manager and in the Slab Style list on the Tool bar.

Creating slabs

Drawing slabs manually

Creating automatically bounded slabs from existing walls

Creating slabs with both automatically bounded and manual edges

Using slab styles


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