by John Flanagan
Working with Constraints in Revit – Levels & Grids
Constraints in Revit allow you to lock elements and establish relationships. In Revit we can use levels and grids to establish some important constraints when setting-up our projects.
Grid Alignment
Alignment is a common constraint. The align function includes the ability to lock the alignment between objects. In the illustrated example the align tool has been used to align and lock the brick wall to grid line 1. The grid line is selected first, then the wall, then the lock. To remove the constraint, just select the wall and then left-click on the padlock symbol. You will see the padlock symbol change to the unlocked position.
Level Constraints
Levels are another datum used to establish wall constraints.
Levels define stories and other vertical heights (such as a parapet or other reference heights). The default template includes two levels, but many levels can be defined as required.
They can go down (for basements) as well as up.
Wall height is controlled by using the Base Constraint and Top Constraint. Set them to the levels you require and use the Base Offset and Top Offset to place them to a specific distance from a level.
You can use a negative value if required. Constraints can be modified at any time, even after the wall is created.
Reveal Constraints
Click the Reveal Constraints icon on the view control bar of the view window. In the temporary display mode all constraints are easy to identify as they stand out in red. Being able to review project constraints is handy for someone who has been introduced to the project at a later stage.