Putting In A Sloped Roof

Courtesy of Capt Bob.

Basically Revit does a terrible job of handling sloped roofs once you have more than one slope or slopes in two directions.  So we have developed a work around.  You can use the roof command structure to develop a roof and attach the columns to the roof.  It is questionable if even this is a good idea, but more on that later.  Once you get that done turn the roof off and never look at it again.  You might even want to delete it altogether. 

Forget that there is any such animal as a roof.  From now on you are working with a floor.  It is just at the roof level.  Do not put in a floor with multiple elevation points and planes.  You are much better to divide the areas into individual sections for each area of your roof.  i.e. if you have a building with a simple gable you have 2 roofs.  If you have a hip then you have 4 roofs.  You can see with some of our multi-slope roofs you will have a lot of different roofs. 

At  this point you can attach your columns to your floor, so as you can see if you had put in a roof it is now worthless.  The main difference is you will have to deal with multiple sections rather than one section for attachment of the columns.  It is your call; I think it is faster to not do the roof. 

Now you have all your columns to the correct height then put beams or beams and joist using the 3d snapping check box.  By doing that you can snap each of the beams or joist to the column.  Now you might have to play with the column height offset at the top between the joist and the beams.  On a recent job I attached the columns to the deck.  Moved them down 2 ½” to put in the joist girders.  Moved them back up 2 ½” to put in the tie joist.  (Poor planning on my part)  Then move them down 9” for the joist girder to sit on top of the column.  Of course you can move all the columns globally and do the change for all of the columns at once. 

Now you have your beams attached to the column in two directions.  If you are lucky you can set your plane to the section of roof you are working in and then enter your joist as a beam system.  If not you can just put them in one at a time using the 3d snapping. 

Why would you not be lucky?  Well there is an issue with a warped roof plane.  Revit just won’t snap to it because it isn’t a plane surface.  The moral to the story is: try not to use a warped plane.  Theoretically what Revit does is correct.  What we all know is the difference between the mathematician and the engineer is we just get it close and say it is good.  You don’t know the joke keep reading.  A mathematician and engineer were placed in a room and a beautiful unclothed woman was placed at the opposite end.  They boys were told they could move toward the woman but could only go half way each move.  The engineer took off and realized the mathematician hadn’t moved.  He turn and ask “WTF Dude you aren’t moving” to which the mathematician replied “you will never get there if you can only go half way each time”.  The engineer took off saying “I can get close enough”. 

More later.  By the way don’t use slabs either.  They have similar issues.  Repeat after me “Everything is a floor”.  Good boy.