Flat Roof specifications

[JJohnson]

I do not think the program can provide tapered joists, but you just call them out on
the plan drawing *( text box with arrow pointing to joists )

Something like, " 2 x 12 joists 16 " o.c., tops sawn to taper for 1/4" per ft. slope."

As others have pointed out sizing and spacing of these would be specified by
an architect or structural engineer. Unless the span table calls for 2 x 8 and
sawing a 2 x 12 would leave no less that the depth of a 2 x 8 when done. A plan
checker may be ok with something like that

To show a tapered joist in a cross section view you can use the CAD tools and draw it so.
To show a tapered joinst in a 3D camera view, you make one from a polyline solid.

There are several ways to get there.

Hope this helps.