Tuesday, April 23, 2013

Window or Door Frame Positioning

We quite often want to be able to move a window or door assembly back and forth within a host wall. This is easy to do as long as the assembly is moving "in" but doesn't need to move beyond the host in the opposite direction. A relationship between reference planes does not generally like to be reversed. We usually get yelled at with a message like this.

When we want the flexibility to move something from or toward something else we need to define an alternate reference point, reference plane in this case. If we place a reference plane in front of the exterior side of the host we can set it far enough away to provide enough room to move the assembly without generating an error message.

In the image above I can move the Frame Offset reference plane "outside" the exterior face of the wall by using a negative dimension value and toward the Interior by using positive values. The fixed dimension value of 12 inches defines the reference offset value I used in the formula column. This means when I enter zero for Frame Offset that the assembly will be flush with the exterior of the wall. Here's what it looks like using a negative 8" offset to move it outside, from the exterior face.

There are firms that use multiple walls to define the layers of what many people use one wall with layers for. When you place walls next to each other a door or window family is hosted by one of them. If you need to move the family "forward or backward" you need to be able to change the notion of what host reference plane is relevant. This is one approach to solving the problem.

1 comment:

Anonymous said...

This is the formula I use for Doors & Windows:

X" = Offset distance to exterior Reference Plane, I set it to 1'-0"
Wall Closure = A = Yes/No Parameter; "No" to activate offset
Object Offset = B = Specify Offset; negative or positive dims
Offset Calc = Y = if(A, X”, if(B < 0”, Z, B + X”))
Negative Calc = Z = if(B < 0", X" + B, X")

…Therefore Set A & B parameters to your prerogative.