REVIT Blog Series with Justin Gillard - Skinning the Mass | Nittygritty
banana peel - skinning the mass

14th Mar 2017

REVIT Blog Series with Justin Gillard – Skinning the Mass

At Nittygritty, we’re so passionate about Revit, we’ve created a blog series – Each month Justin Gillard will walk us through some effective ways to use Revit.

3D modellers challenged by the tools of Revit’s Project environment be aware, achieving complex faceted, curved and NURBS forms is possible. For this, Revit’s In-Place-Mass tools make available a number of modelling methods able to achieve your design. Furthermore you can also derive your Mass form from Linked models authored in other software like Rhino, Maya®, 3ds Max®, Trimble® SketchUp®, or Form/Z®. But, to make the resulting form a Categorised building Element that responds to View Settings we have to learn how to ‘Skin The Mass’


Justin Gillard, BIMgineer® and Sr. BIM Consultant

14th March 2017

Skinning The Mass (in 5 steps)

Skinning the Mass


Skinning the mass –  In this blog I am going to take an already modelled/Linked Mass form and effectively convert it to ‘native’ Revit building Elements using the Model By Face tools. This way we get all of the benefits that using Materials brings e.g. View Overrides and quantification in schedules. You may have a situation as in this example where the structural form required the use of the Mass tools but you require the Mass itself to behave as the rest of the building, and hence need to ‘Skin’ it.

Step 1

Setup the 2D Views perpendicular to the faces of the Mass to be used when applying the Materials to the Mass’ faces include a 3D View if it helps.

Perpendicular View

Step 2

Create the Materials that you intend to ‘Skin’ (apply) on to the faces of the Mass.


Beyond the appearance the Materials will give you, there is the opportunity to invest some embedded data that can be scheduled to glean surface area. If you’re looking for Volume you should use the underlying Mass for this and other types of analysis.

Step 3

Create Wall and Roof Families which will become the ‘Skin’ of this Mass and attribute the previously created Materials to them.

Roof  Wall

As the Wall and Roof Families will form the ‘Skin’ on the faces of the Mass, they are required to be thin. Thickness: 1.0mm is about right as you will not want your Mass to grow outward unnecessarily.

Tip: Remember to set the Location Line: Finish Face: Interior as this will place the ‘Skin’ on the outside of the Mass. location

Step 4

Now we begin the process of ‘Skinning the Mass’. The tools used are the Massing & Site>Model by Face tools: by Roof or Wall.


Tip. Add these tools to the Quick Access Toolbar for this process as they will be well used.


The Wall by Face tool will apply the Wall Family to most Mass surfaces but has its limits, if/when this happens, use the Roof by Face tool instead. If neither tool works simplify the Mass surface in to horizontal and other planes/curves.

First Select the Wall by Face tool then the Basic Wall: SKIN-Steel Family Type. In the examples below the majority of surfaces are ‘Skinned’ using the Wall by Face tool.


To avoid the ‘Skinned’ faces overlapping where parts of the model(s) touch, before ‘Skinning’ select and isolate the required Mass.

Highlighted below is one face that will not ‘Skin’using the Wall by Face tool.


The Roof by Face tool is instead used to ‘Skin’ the flat underside of the form. All horizontal faces require this tool. Remember to Create Roof to manifest the ‘Skin’.

Continue applying these tools, and the appropriate ‘Skin’ Material, to the entire form until you have a fully ‘Skinned’ form. In the example below I have used steel and concrete ‘Skin’ Materials for the different parts of the structure.


Step 5

With all faces of the Mass now ‘Skinned’ you can turn off the Mass Category leaving the ‘Skin’. If the Mass requires further design development, simply Modify Revit’s In-Place-Mass using the relevant tools or re-Link the form from Rhino, Maya®, 3ds Max®, Trimble® SketchUp®, or Form/Z®and Update to Face!



Revit’s In-Place-Mass tools are versatile enough to facilitate the creation of any building form and beyond that allow the manifestation of Materials on to its faces effectively converting the Mass from to building Elements. If you would like to know more about this process or any other advanced creation methods please make contact with Nittygritty.Net Ltd.

Check out our other posts on working effectively with Revit

Modelling in Family Editor Environment 

Modelling in Place in the Project Environment 

Next Blog

“SketchingUp in Revit”. Learn how to ‘sketch’ model forms using the techniques commonly applied to SketchUp, using Revit’s tools