Need a higher rear wall due to different roof pitch - how to make it happen?

[diyconsulting]

U know this brings me to ask for a change in the term baseline. Why cant chief simply do away with baseline and use wall top plate instead? I mean the roof sits on a top plate...the top plate gauges ceiling framing height...we go to all the trouble of setting up room defaults inc ceiling height...to my way of thinking, this idea of persisting with an arbitrary point called roof baseline is ridiculous!

Id like to see a builder running a stringline along chiefs "roof baseline" in order to pitch a roof!!! (that will be the day when pigs really can fly)

[Bradley Boltz]

I would like to see the continued use of "baseline" as well as a Top Plate or Bearing Plate designation for creating roofs. When you designate a ceiling hgt for the room you are drawing the roof on, you are using the Top Plate as the bearing point. The "baseline" is important because it's the same as the HAP (Height Above Plate) that is a helpful number to a roof framer. You can't properly cut rafters if you don't know what your HAP is. My roof framing book always recommended a HAP of at least 2/3 of the total rafter depth (measured perpendicular to the slope of the rafter). This keeps your HAP from being too short and weakening your rafter at the shear point where it bears.

I mistakenly thought that the bearing lines would be user definable for heights and that you could draw your roof from a bearing line without walls. To me that would be a nice tool since roofs don't need walls or rooms to exist (but they currently need walls and a room designation in order to be created).

Another thing that would be nice is the ability to select any horizontal (eaves) roof edge and find out what it's elevation is. Currently, you can only do that with a roof plane that has only one eave line.-BB

[CliveD]

Hi and others, I may be miss-interpreting this thread but I have been bulding Roof planes WITHOUT walls for many versions, just created a porch roof now in V5 by draging a roof plane baseline outside of the floor plan (I usually set up 2D lines to follow)
In the picture attached I drew the 2 roof planes at the defautl baseline ht. & connected them. I have subsequently raised the lh plane and draged its rear edge back into the existing building roof. Further editing would normally be done to get the roof planes correct in plan view.

[Bradley Boltz]

Now I'm missing something. How are you controlling or establishing a default baseline hgt? Is it just defaulting to the baseline height for the main structure that you do have walls with a roof drawn on? What if you wanted that porch roof baseline height 2 ft higher (or however cm higher)? Obviously you could draw it at the default baseline hgt then raise the roof 2' but you can't change your baseline hgt from what's already drawn? Correct? Will have to continue tomorrow, the wife calls. Have a nice downunder.-BB

[Glenn Woodward]

Brad,

When you draw a roof manually without any defining structure, the Baseline height is determined by the floor's default ceiling height.
So you can draw a manual roof plane at any height by changing the floor's default ceiling height.
Otherwise, when you draw a roof over a defining structure (wall/room), the Baseline height is determined by the ceiling height of the room.

But, in either case you may still have the added complexity of calculating Chiefs baseline height relative to the plate height.

Another thing that would be nice is the ability to select any horizontal (eaves) roof edge and find out what it's elevation is. Currently, you can only do that with a roof plane that has only one eave line.-BB

I don't understand this - can you expand?

[mkennedy]

I think the whole paradigm needs to change. I just drew a plan with a similar condition, except that the higher plate height only affected a segment of the wall. I would have had to create 2 invisible walls to raise the plate height. Rooofs aren't really built by the room, anymore than the second floor plan interior walls are aligned with first floor walls.
Sometimes a roof does what ot does for a logic other than room ceiling heights.
I love the auto roof tool, I can get an as built shell roughed in, build the roof, start tweaking to get the roof to match as built conditions. Then I run into this condition and have to turn it off. I'd really liek to manually tweak the roof , break the wall, assign the new plate height (copy pasted from the roof plane, maybe automatically?) to the wall segment, have that info locked and leave the auto build function on.

[amddrafting]

Really it seems in this case the easiest solution, if you insist on using automatic roof planes is as follows:

1. build your front and rear roof planes over the garage at the 10:12 pitch.
2. Open the rear roof plane dbx
3. Lock the roof ridge height by clicking on the radial button
4. Set your pitch to 5
5. Exit out and you're done.
6. Next open the wall dbx and go to the structure tab
7. Set wall to "balloon through ceiling"
8. exit out and you're done.

If you want the ridge to be in an different location then drag the front roof ridge to the location you want it. Then open the roof plane and take note of the ridge height (highlight and copy would be advised). Then move your rear roof plane ridge to the front plane ridge. Open the rear dbx and lock the pitch and then in the ridge tab enter in the value of the front roof ridge height (highlight right-click and paste). That's all it takes to accomplish this task.

I've said this before but it is definitely advised to learn how to manually create roofs. Your options are limitless when you do so. They are easy once you figure them out.