Creating Common Types of Dynamic Components

I have a problem related to a topic illustrated in the User Guides, namely “Repeating a sub-component within a dynamic component (1 Dimension)”. At point 16 it is written “Type =5+COPY*(Fence!spacing+LenX)”, what does the 5 represent?
Thank you

5 is the first position
copy is a read only attribute with a value equal to the copy number
for original this is 0, next 1, then 2,…to N where N = copies

… but 5 has a unit of measurement or not

no need, the default in this case is inches

the formula is read as a value in inches

Sorry if I insist, I write from Italy, so I have to convert inches into cm, what I’m interested in knowing is: the 5" represent the dimension of what? Attribute? or sum of Attributes? or what?

No you can work in cms, you choose at two points as needed, if required

let’s assume you are using cm

the original (copy = 0) would evaluate to 5cm
the next would the 5 + the picket(lenx) and the spacing
the second copy = 5 +2 times(picket(lenx) and the spacing)
and so on…

for most if you define the unit then a formula will respect the unit chosen

Ok, now yes, many thanks

The DC units house of cards collapses if the “display units format” box is not checked in Window>Model Info>Units. Bug found about 15 years ago already.

I forgot a clarification: the formula =5”+Copies*(Fence!spacing+LenX) should be inserted in Picket > Position X ?


As the Pickets increase, the TopRail and BottomRail, while not having locked their respective LenX, do not resize automatically. Is there a way for this to happen? Or do you just have to do it manually?

You can set a formula to calculate the LenX for the rails.

I wrote an improved version of the SU simple Picket Fence, which illustrates this:

Fence±+picket.skp (176.2 KB) (SU v2015)

The right hand post is not part of the Dynamic Component, but copied manually.

I was working in inches, but the principle is the same.

Here are the DC options:

The fence length is adjusted by using the Scale tool - only the X dimension is scalable.

The timber sizes are ‘nominal’ sizes - in the UK, normally 1/4" smaller in the actual dimension than the nominal size, because of planing allowance. So a post made from 4" x 4" sawn timber 100mm x 100mm (nominal) would end up 3 3/4" square or approx 94mm square after planing smooth.

USA and Canada have larger planing allowances - normally 1/2" or about 13mm.

In BottomRail (in my case in Italian: TraversaInf) > LenX I inserted the formula you suggested =Fence!LenX-Fence!PostSize (=Recinzione!LenX-Recinzione!PaloDimensione) and it gives me an error
Uploading: image.png…
Uploading: Errore LenX (TraversaInf).png…

For john mcclenahan

Dynamic Components Math Function Examples | SketchUp Help