Walls, floor slabs, flooring, ceilings and roofs in Snaptrude are built from construction layers: one or more structure layers plus any finish layers. The layers set the object's overall thickness and carry through to Revit one-to-one, and you can attach custom properties to these objects for scheduling, costing and export. Use this article to understand how thickness and layers relate.
Before you start
Construction layers and BIM object types belong to BIM Mode, which is available on the Pro, Organization and Enterprise plans.
Team libraries are available on the Organization and Enterprise plans.
The behaviour described here applies to projects created after construction layers were aligned with object thickness. Older projects can behave differently.
How thickness relates to construction layers
An object's thickness in the Properties panel always equals the sum of its construction layers, so the total and the layers stay in step.
Structure layer: the core of the wall, slab or roof. When you change the object's thickness, this is the layer that changes.
Finish layers: the layers on either side of the structure. Changing the object's thickness doesn't change them.
If a type has more than one structure layer, a thickness change is split between them in proportion to their current thicknesses.
Change a wall's or slab's thickness
Select the wall, floor slab, flooring, ceiling or roof.
In the Properties panel, enter a new value in the thickness field (for roofs, Roof Thickness).
The structure layer grows or shrinks by the difference, and finish layers are unchanged. Push-pulling a lateral face of a wall or slab works the same way: only the structure layer changes.
Note: Columns and masses don't have a thickness field in the Properties panel.
Understand "Variable" layers
If you reshape an object by moving its vertices or edges, its thickness may no longer be uniform. In that case the structure layer is set to Variable, because it can no longer be described by a single number.
Tip: If you need a uniform build-up for documentation or Revit export, avoid vertex and edge edits on walls and slabs.
Use the generic types
The library includes a set of default types for each BIM category:
Category | Default types |
Wall | Generic Wall |
Floor Slab | Generic Slab, Metal Deck Slab |
Flooring | Generic Floor |
Ceiling | Generic Ceiling |
Roof | Generic Roof, Metal Deck Roof, RCC Roof, Asphalt Shingles |
Metric and imperial projects use different default libraries. For example, Generic Wall is 100 mm in a metric project and 3 5/8" in an imperial one.
Add finish layers by applying materials
Applying a material to a wall or slab with Materials (B) on the right-edge toolbar adds finish layers to it:
Applying a material to a single face adds one finish layer.
Applying a material to the whole object adds two finish layers.
Because thickness is the sum of the layers, adding finish layers increases the object's overall thickness.
Review layers before export or costing
Select a BIM object to review its construction layers before you export or cost the model. For quantities, open the Take-Off tab in the right panel in BIM Mode, or use the project menu > Export > Take-off.
Add custom properties
Custom properties let you attach your own data, such as a fire rating, manufacturer or specification code, to floor slabs, flooring, ceilings and roofs. Snaptrude keeps a changelog of edits alongside these properties and costs.
Team libraries also hold costing information for types, with a currency picker so costs show in your team's currency.
Send layers and properties to Revit
Construction layers map one-to-one to Revit, so a wall or slab exported through Snaptrude Manager arrives in Revit with the same build-up.
Custom properties export to Revit as shared parameters.
Exporting to Revit needs Snaptrude Manager and isn't available on the Free or Starter plans. Accept Snaptrude Manager's update prompts so construction layers transfer correctly.
Troubleshooting
Thickness changed more than expected after applying a material. Applying a material to the whole object adds two finish layers. Apply it to a single face if you only want one.
The structure layer shows "Variable". The object was reshaped with vertex or edge edits, so its thickness is no longer uniform.
A wall stopped updating with its neighbours. Changing the type or thickness of a parametric wall created with Sketch to BIM turns it into a non-parametric wall.
Related articles
BIM Mode overview
Team Libraries and Wall Types
Export to Revit with Snaptrude Manager
Working with Roofs