Someone asked this question on SoftPlanTuts Chat last night.
need to know how to do a step down truss for instance one end plate hgt. is 10' the other is 9' but i want my fascia all to be level
I responded asking them to please ask the question on the Forum so I could get more information and better respond and illustrate how to do it. I have to admit that I was also stalling because I didn't have an answer right off the cuff. I don't use trusses so I haven't drawn many before. But I had some ideas to try. The person asking the question never responded nor did they provide any additional information so I may or may not be accurately responding to what they were looking for.
You can click on any of these images to see a larger version if you wish.
The first thing I did was draw up a simple rectangular plan with the left side being 10' tall and the right side being 9' tall. I popped on a roof and as I expected the roof was lopsided. But I knew that I could straighten it up by editing the side of the roof that was on the 9' plates.
On the right side I edited the roof edge and added 12" to the Heel Height. This automatically activated the Energy Heel option for that side of the roof and raised the fascia up 12".
This straightened up the roof so the fascia was the same elevation on both sides.
So then I added a truss, expecting it to follow the shape of the ceiling. Trusses will follow the shape of a ceiling such as in the case of a cathedral ceiling. But apparently not in this case. Here is the result.
If you will look at the ceiling portion of the truss you will see that it just angles down from the high side to the low side.
So that didn't work. Next I tried breaking the truss into 2 trusses. One on the high part and another on the low part. For this to work I needed to use a Bearing interior wall. So in the Wall Definitions I made a copy of the interior wall and set it to bearing. I changed the interior wall on the plan to to this new Bearing wall. Now I can see the wall in Roof Mode and I know where to make the break in the truss.
I drew in a truss on the left going from the roof edge to over the bearing interior wall. Then I drew another truss starting at the end of the first truss and going to the edge of the roof on the right.
And here is the result. The truss correctly follows both the roof and the ceiling and the fascia is at the same elevation on both sides of the house.
Bill is the owner and maintainer of SoftPlanTuts.com