bridsmouth set to zero only works for one type of the roof planes

[SHCanada2]

I am adding a sunroom to a house. The main house is 2x4 roof, and the sunroom is 2x8 rafters.

 

I set the birdsmouth to zero in the build roof dialog. It works for the main roof and the sunroom, but then I need to change the roof structure of the sunroom roof plane to 2x8. In doing so, it turns off the autobuild. CA puts in 2x8 rafters but does not adjust the rafter to be sitting on the top plate,. instead it creates a weird birdsmouth. Its like CA is using the VSD for the 2x4 roof for the 2x8 sunroom roof.

I can certainly raise the sunroom roof planes using TNR, but wondering if this is the expected behaviour?

the problem with raising the roof plane is...by how much...need to do the math on the VSD of 3.5@4:12 compared to VSD for 7.125 @3:12?

 

on another note, there looks to be a bug with box windows if the roof below it is too close to the bottom of the box:

james.plan

[SHCanada2]

so i decided just to make all of the rafters 2x8 in the defaults and then autorebuilt all the roofs.

 

works for the top roof but the sunroom is still showing birdsmouth

 

if I delete the roof plane, it shows top of plate at 9'9 and nicely aligns with the main building top of plate

 

but when I turn on the auto build roofs it then shows 9'11 and no longer matches the main building

any idea why?

 

[Chopsaw]

27 minutes ago, SHCanada2 said:

the problem with raising the roof plane is...by how much...need to do the math on the VSD of 3.5@4:12 compared to VSD for 7.125 @3:12?

 

3.6893"  vs.  7.3442"    but I think you mean 7 1/4" and that would be 7.4731" for VSD.

[SHCanada2]

so if I check "flat ceiling over this room", the top of plate goes back to 9'9 and all is well. What the heck is going on?

 

 

[SHCanada2]

4 minutes ago, Chopsaw said:

3.6893"  vs.  7.3442"    but I think you mean 7 1/4" and that would be 7.4731 for VSD.

right, so am I supposed to do that math (subtract them) and then TNR, or is there another way?

[SHCanada2]

for some reason the baseline is auto building inside the wall

\

 

and if I manually move it to the wall, then my top plate is at 10'

 

[Chopsaw]

Yea I think that is the way to go about it.  Possibly the other issues you are seeing are a result of auto rebuild not actually adjusting the existing roof height for the framing change.

[Chopsaw]

1 minute ago, SHCanada2 said:

for some reason the baseline is auto building inside the wall

 

That might account for the irregular birds mouth but I am not sure I can explain it.  These things sometimes turn into a lengthy science experiment to understand the programming.

[SHCanada2]

2 minutes ago, Chopsaw said:

Possibly the other issues you are seeing are a result of auto rebuild not actually adjusting the existing roof height for the framing change.

i deleted the roof plane, and rebuilt all roofs with 7-1/4. so not sure why it would not build on top

[SHCanada2]

19 minutes ago, Chopsaw said:

Yea I think that is the way to go about it

it still doesnt seem to work. it looks to be putting in a top plate 

 

if i lower the baseline by 1.5 it is the correct top of plate

but it is birdmouthed

 

[SHCanada2]

if i raise it 12" i can get rid of the birdsmout. this seems like the old roof problem where it builds the wall up under certain conditions

 

[Chopsaw]

I am not sure what is goon on Jason, I did a little test plan and tried raising the roof plane with TNR and it went crazy.  Did the exact same thing with an individual rafter and it was fine.  You might want to send this one in if it does not sort itself out.

 

If @solver is around he might be willing to give it a go.

[SHCanada2]

thanks for validating @Chopsaw