BILT Speaker

BILT Speaker
RevitCat - Revit Consultant

Monday 3 February 2020

Room Bounding Structural Column Materials in Revit

I recently discovered yet another obscure, hidden away setting in Revit - when I was investigating the "Room Bounding" property of different elements.

It seems that some structural columns have a "Room Bounding" property - but not all.
This has to be one of the weirdest, arbitrary decisions made by the Revit programmers:

Material for Model Behaviour

Structural columns have a weird property - so obscure and arcane, not to mention hidden away.
'Material for Model Behavior'

This property that can only be set in the Family Editor – in ‘Family Category and Parameters’: ‘Material for Model Behaviour’.

It can be one of 5 settings, each of which enables different properties and behaviour in the model:
  • Steel
  • Concrete
  • Precast Concrete
  • Wood
  • Other
Depending on which one you choose, it will enable properties in the family.
  • Steel has Connection properties
  • Concrete & Other have Rebar properties

These settings are hidden away behind the 'Family Category and Parameters' settings - in the project there is no way to tell which setting the family has, apart from the specific properties displayed.

You would have thought that this only affects structural engineers?

But wait.  It affects architects too . . . . .
  • Concrete has ‘Room Bounding’ properties (it is the only one that does)

Why, oh why are wood and precast concrete not room-bounding?  There are a huge number of timber structures around the world that provide perfectly good enclosures.
Wouldn't it just have been easier to make all columns potentially enclose rooms, instead of hard-coding someone's bizarre ideas about how a building might work?


When working in a project, and you discover that a 'Room' is not enclosed when you expect it to be, this is one of many things to check.
There are some other quirky Room-Bounding behaviours in Revit, to be detailed later  . . .