Auto foundation

[Novasceo]

Why does an automatically generated foundation have dimensions 2 1/2" narrower than the floor above?

I drew a 1st floor 18' x 28', and the foundation Suite 9.0 generated is 17'- 9 1/2" x 27' - 9 1/2".

I'm guessing it is subtracting sheathing and siding thicknesses so that the framing lines up with the foundation. But does anyone specify building dimensions at the outside of the siding? I guess if you start with the foundation, it would work fine, but that defeats the value of auto-generating the foundation.

[Elovia]

The answer to your specific questions depends on many different settings, and how you have them defined. We can only guess as to the cause. The root of your question is how measurements are made; or more precisely, to where and from where are they made?

You suggested that your software measures from the outside of the siding to the outside of the siding on the exterior walls. Did you customize the wall definition? Which defined wall type are you using? Does it have default behavior? The same questions apply to the foundation wall type.

The only version 9 software I have is the Pro 9 trial, and the default exterior wall is Siding-6 therein. Temporary measurements are not made to the outside of the siding, but instead are made to the exterior surface of the studs.

To follow your example, in Pro 9 Trial, I drew four exterior walls and set the dimensions exactly 18' x 28' by precisely moving them using the temporary dimension lines. I then created a default foundation based on the first floor. The foundation measurements are also 18' x 28' as created (no adjustment done). With the reference display option turned on, I can see the foundation exterior surface and the exterior side of the studs are aligned. If your behavior is different, then you might have changed a default setting. Double check your settings to verify they are correct so you can get the best use of your tools.

Hope this helps.

[Novasceo]

I am using the defaulted Siding-6 exterior wall. I have made no changes.

I just did exactly what you did -- drew a simple four-wall floor, then added an auto foundation. I am attaching two images showing what I see on screen.

The Auto Exterior Dimensions feature is clearly measuring to the outside of the siding, and the reference display clearly shows that the sheathing and siding are outside the foundation perimeter. This makes sense, but it means that to get accurate dimensions, you have to build the foundation manually or resize the walls to accommodate the sheathing/siding thickness.

Hard to understand why the behavior of your Pro trial is different than my Suite version!

[Elovia]

Ah hah ... you're using the Auto Exterior Dimensions; that's the big clue. Go to your Default Settings -> Dimension -> Dimension Defaults -> Locate Objects tab ... now check to make sure in the Walls section that you have the button on the Wall Dimension Layer and not on Surfaces. You will likely need to rebuild your Auto Exterior Dimensions, and hopefully that won't throw off any of your other dimension designs.

As for subscribing ... I can't say since I don't use that feature. I just stop by fairly often.

Edit: if you look at the top of the page, you may see a widget labeled "Thread Tools". If you click on that, a drop down selection box appears and you can subscribe to the thread that way.

Edit 2: The thought just occurred to me that you shouldn't constrain yourself to a single set of dimension tools (i.e., Auto Exterior Dimensions). You may also add Manual Dimensions for specific areas of interest, and you can manually adjust the end points of those dimension lines to better reflect your points of reference for measurement. Likewise, the temporary dimensions are useful when laying out your plan.

[Novasceo]

Alas, I think the issue may be that Suite does not have the richness in it's settings to do what you suggest. In the Default Settings-> Dimension dialogue, there are no tabs, just a few simple selections. And the "manual dimensions" are extremely limited -- I cannot control their endpoints!

I can select the dimension lines and move the endpoints. But the snap behavior is mysterious. The reference manual says I can "edit extension lines" by dragging one of the handles to add new extension lines, then drag the endpoint of the dimension to the new lines. I have played with this for a while -- Suite 9.0 has object snap always on, but the stud surface is not one of the snap points. And there are no walls without siding in the list of available wall types.