Linear Attachments are openings such as windows, doors, or simply openings, that can be placed on linear takeoff.
For our example, we start out by drawing a linear object that is 10' long. The Linear Takeoff Item is 8'00 high so our Results are 10 LF and 80 SF.
Now, we place our Attachment, a door that is 36" x 80", on that wall. The parent object is 10 LF long, so we know the Attachment "fits" on the parent object, with room to spare. Remember, an Attachment's "Width" dimension, must be shorter than the length of the takeoff object onto which you want to place it. Height matters but does not prevent placing an Attachment - we cover that below.
A door is a Linear Attachment, and has no depth - it conforms to the depth of the Linear parent wherever it is placed. For example, this door could be placed on a wall that is 4" thick or one that is 40" thick, it 'cuts-through' the entire wall, no matter how thick that wall is.
Attachments only affect the Parent's Results if you select the "minus attachments" Results in the Parent's Takeoff Item Properties. Linear Attachments only affect the parent Takeoff Item's length results if the Attachment's Height is taller than the parent Takeoff Item's Height.
Notice the changes to the visible Takeoff, and the Takeoff Item's Results.
Because one of the parent's Results is "Surface Area (single width side - minus Attachment areas)", the program accounts for the reduced surface area of the door (important for brick facades or wallcoverings). Notice also that the LF of the Wall has not been affected - because the Attachment's Height is less than the Parent's (the parent is 96" (8') tall and the door is only 80" tall), there is still some wall left for which we must account. Had the Attachment been as tall or taller than the Parent Takeoff Item, the LF would be reduced also (depending on which Results you choose for the Parent Takeoff Item, of course).
By using a Linear Attachment, we not only accounted for the Door and its trim, but accounted for the the reduced surface area of the Wall into which the door is to be installed.
If you do not want to reduce the parent object's surface area Result (perhaps that is how you account for waste), just select a Result that does not include "minus attachment..."
Before drawing any
takeoff, you must set and
verify Scale, see Related Articles.
Drawing Attachment Takeoff