Creating Sloped Roofs

Instructions for creating a roof system based on a joist bearing and roof slope:

1. Create your grids, walls and beam and column layouts. Beam and column elevations are not necessarily important yet.
2. Create a level at a known joist bearing, name it something that makes sense so you can find it later.
3. Go to your sketch plan for framing (You do have two framing plans, right? One for modeling, the other for printing.) and set the Work Plane to that new level.
   
4. Create a roof deck using the slab command. Once you have the deck outline draw a Slope Arrow, place the tail on the known joist bearing elevation. The slope arrow does NOT need to be placed within the deck boundaries, and can stop an start anywhere.
5. With the slope arrow highlighted click the properties button (or hit Alt+Enter).
6. Under Constraints, change "Specify" to "Slope". Level at Tail will stay at "Default". Change "Height Offset at Tail" to 2.5 inches (or a known joist bearing depth).
7. Under Dimensions, change Slope. You can enter a formula too (=-.25/12) = (-1/4"/ft).
8. Finish the slab sketch, and create a section thru the new deck, parallel to the joists you want to place.
9. Open that section view, and change the Detail Level to Fine. If the deck is spanning the wrong direction, you can rotate the Span Direction arrows 90° from the plan view later.
   
10. Draw a new Ref Plane at the bottom of the deck, and in the properties name it something useful (B/D at High Roof, for example).
11. Switch back to the framing plan, set the Work Plan to the new Reference Plane, and start the Beam System command.
12. Sketch the outline of the beam system, set the spacing and beam sizes. Finish sketch.