# Assembly Properties The bimCAT Library Browser supports setting a number of assembly properties to the family types, both for the [Current Project](https://docs.bimcat.org/user-manual/usage/library-browser/current-project) and [Library ](https://docs.bimcat.org/user-manual/usage/library-browser/library)items. The assembly properties are supported for the following Revit categories: * [Ceilings](#ceilings) * [Columns](#columns) * [Floors](#floors) * [Roofs](#roofs) * [Structural Columns](#structural-columns) * [Structural Framing](#structural-framing) * [Walls](#walls) To set these properties, the user needs to enter the **Compare Assemblies Mode**. This is done by selecting a family type belonging to one of the supported Revit categories and clicking the **Compare \[Category]** button in the right pane.
The **Library Browser** will then enter the **Compare Assemblies Mode** in which only the elements of the chosen Revit category will be visible along with additional set of property columns depending on the Revit category.
Unlike the rest of the columns, the assembly properties could be directly edited in the table.
If you want to change a property for multiple rows at once, select the rows you want to edit using the checkboxes on the right and then edit a property in one of the selected rows. This will result in changing this property for all the selected rows. This feature works both for drop-down lists and edit boxes.
To exit the **Compare Assemblies Mode**, you can either click the **End Compare** button in the right pane, or close the category tag displayed in the toolbar.
Next to the new assembly properties column, the library grid will have one more column responsible for saving or reverting changes done to the assembly properties.

The Save All button allows to save the changes for all modified items

The Save button saves the changes for a specific family type

The Revert button allows to undo changes for a specific family type

When the buttons are in a disabled state, nothing could be saved or reverted here

If the user attempts to exit the **Compare Assemblies Mode** while having unsaved changes, the will be prompted to save.
Apart from the dedicated columns, the assembly properties are also displayed in the right pane.
Also, they could be seen in the **bimCAT Properties Viewer**.
Also, in the **Compare Assemblies Mode** the GWP columns will display a **mini-bar chart** which will makes easier to compare the corresponding values.
The assembly properties are saved to the library and could be transferred from one project to another together with their family types. The set of assembly properties available for each supported Revit category is different. Here's a brief description. ### Ceilings The following assembly properties are available for this category: * **Fire Rating** - a number from the fixed list: **0.5, 1, 1.5, 2, 3, 4**. Unit: **h**. Default value: **none**. * **Thickness** - a number. Unit: **mm**. Default value: **the thickness property of the corresponding Revit assembly, if available**. * **Thermal Resistance** - a number. Unit: **RSI**. Default value: **none**. * **STC** - an integer. Unit: **dimensionless**. Default value: **none**. * **Impact Insulation** - an integer. Unit: **dimensionless**. Default value: **none**. Here's an example on how this set of assembly properties looks in the **Compare Assemblies Mode**.
### Columns The following assembly properties are available for this category: * **Column Type** - a type from the fixed list: **Architectural, Structural**. Default value: **none**. * **Fire Rating** - a number from the fixed list: **0.5, 1, 1.5, 2, 3, 4**. Unit: **h**. Default value: **none**. Here's an example on how this set of assembly properties looks in the **Compare Assemblies Mode**.
### Floors The following assembly properties are available for this category: * **Floor Type** - a type from the fixed list: **Slab on Grade, Suspended**. Default value: **none**. * **Fire Rating** - a number from the fixed list: **0.5, 1, 1.5, 2, 3, 4**. Unit: **h**. Default value: **none**. * **Thickness** - a number. Unit: **mm**. Default value: **the thickness property of the corresponding Revit assembly, if available**. * **Thermal Resistance** - a number. Unit: **RSI**. Default value: **none**. * **STC** - an integer. Unit: **dimensionless**. Default value: **none**. * **Impact Insulation** - an integer. Unit: **dimensionless**. Default value: **none**. Here's an example on how this set of assembly properties looks in the **Compare Assemblies Mode**.
### Roofs The following assembly properties are available for this category: * **Roof Type** - a type from the fixed list: **Steep Slope, Flat, Vegetated**. Default value: **none**. * **Fire Rating** - a number from the fixed list: **0.5, 1, 1.5, 2, 3, 4**. Unit: **h**. Default value: **none**. * **Thickness** - a number. Unit: **mm**. Default value: **the thickness property of the corresponding Revit assembly, if available**. * **Thermal Resistance** - a number. Unit: **RSI**. Default value: **none**. * **STC** - an integer. Unit: **dimensionless**. Default value: **none**. * **Impact Insulation** - an integer. Unit: **dimensionless**. Default value: **none**. Here's an example on how this set of assembly properties looks in the **Compare Assemblies Mode**.
### Structural Columns The following assembly properties are available for this category: * **Column Type** - a type from the fixed list: **Architectural, Structural**. Default value: **none**. * **Fire Rating** - a number from the fixed list: **0.5, 1, 1.5, 2, 3, 4**. Unit: **h**. Default value: **none**. Here's an example on how this set of assembly properties looks in the **Compare Assemblies Mode**.
### Structural Framing The following assembly properties are available for this category: * **Fire Rating** - a number from the fixed list: **0.5, 1, 1.5, 2, 3, 4**. Unit: **h**. Default value: **none**. Here's an example on how this set of assembly properties looks in the **Compare Assemblies Mode**.
### Walls The following assembly properties are available for this category: * **Wall Type** - a type from the fixed list: **Exterior, Partition, Retaining**. Default value: **none**. * **Fire Rating** - a number from the fixed list: **0.5, 1, 1.5, 2, 3, 4**. Unit: **h**. Default value: **none**. * **Thickness** - a number. Unit: **mm**. Default value: **the thickness property of the corresponding Revit assembly, if available**. * **Thermal Resistance** - a number. Unit: **RSI**. Default value: **none**. * **STC** - an integer. Unit: **dimensionless**. Default value: **none**. * **Load Bearing** - a boolean: **True, False**. Default value: **none**. Here's an example on how this set of assembly properties looks in the **Compare Assemblies Mode**.