Tuesday, January 10, 2012

Side effects of using out of the box door families

Many of the families that come with Revit by default out of the box are very nice, basic and do what you need them to do in your project.  Unfortunately, the doors are not one of those, at least not for the kind of projects that most of us usually do (non-residential).


For residential projects, the out of the box Revit doors are basically what you need them to be.  Simple, dimensional, and containing trim.  For commerical work, the doors will simply not suffice, mainly because of the way that they cut the walls and display in elevation and floor plan views.

Let's look at an example. 
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The above is a regular out of the box revit door inserted into what amounts to a very thick wall assembly.  According to the door schedule on the project, this is a normal hollow metal door, sitting in a frame, somewhere inside the assembly of the wall.  Because this is a staircase, the door swing is important, because an infringement into the clear space of the stairs is an egress issue addressed by the code.  However, because the fact that an out of the box door was used, the door automatically aligns with a face of the wall, thus graphically incorrectly showing it's location, swing and clearances.

The out of the box families include trim on the door, no frame, but instead trim, which automatically positions itself on the inside and outside of the wall (much like you would put in a residential setting).  Take a close look at the wall on both the exterior and interior of the door, you can make out a little something.  That is the trim.  This can pose issues when looking at a floor plan, and unless something is modified in the schedules and formulas are added, there is no way to know what the actual rough opening of the wall should be.

In the example shown above, someone actually went in and drew lines connecting the trim on each side of the wall to make it look like a frame was present in plan.  The only issue with this method... your apparent 'frame' doesn't cut the wall.  Instead you are just drawing a line through the wall.

Typically on a plan, you would show the frame is shown as part of the door assembly in the wall and cuts it all appropriately.  Doors can be a pain.  They can be incredibly powerful tools, and work in your schedules all automatically and all parametrically.  To get doors to this point however can require a lot of work.  It can require making lots of custom families and components, using shared parameters between families, nested families and their hosted project.  I even have gone as far as making frames contain different detail levels to show more or less detail depending on the detail of the view they are displayed in.

There are new tools, add-in's to Revit which are being developed to assist the creation of door families, their schedules and how they interface with door and hardware suppliers.  I am lucky enough to get an opportunity to beta test one of these programs.  At the moment it looks promising, and can completely take away tne need to spend lots of time making custom families.